Anje, Hopeful it is now clear that if you set an account to sync X days, you still see all your emails, even those older than X days. Also, when you access (read) an email older than X days it gets stored in the mbox file but is marked "pending removal" and it will only be removed when the folder is compacted. So the mbox can still get bigger than it would be with just 30 days of email. This can be managed so you get an auto-compact prompt by setting the advanced parameter **Compact all folder when it will save over Y MB in total**. Or you can also manually select the large folder and compact it. This won't delete any messages that were not already "IMAP marked for deletion" from the server. Then you bring up issues with reading messages offline. When you click the "two blue screen" icon and go offline it prompts to download all folders in all accounts or don't download (i.e., Later). If you choose to download, all your emails that are not already downloaded in all accounts and folder will be downloaded. However, the emails that are not configured to be synced in an account (older than X days) will still be downloaded. However, when stored in the mbox file they will (or should) be marked "pending removal". Now you can read all your emails in the folders of all your accounts. Regardless of the "sync X days" setting, for offline use *all* mail must be downloaded in the folder so it works the same as it did when online. Alternatively, when you want to go offline and you anticipate that you only need one or two folders to read, you can right-click on the folder(s), select them for offline (checkbox) and download only those folders (button) and then go offline and select "Later" so nothing more is downloaded. In this case, all the emails in just that/those folders(s) will have downloaded but those older than X days are marked "pending removal". (Note: if you fail to tick the **Select this folder for offline use** checkbox and just click the "Download now" button, the created mbox file seem to not have any old entries marked "pending removal". Seems like a bug.) In both offline cases, when you go back online and if the total size of messages in mboxes marked "pending removal" exceeds Y in the **Compact all folders when it saves over Y MB in total** parameter, you will be prompted to compact all the folders. Or you can always manually compact them. In the 2nd case, you should also clear the offline selection for the folders you selected for offline use so the mbox files remain empty. (In reply to Anje from comment #10) > However, you get all kinds of changes if you go into offline mode, but not perhaps the one you necessarilly expect. > Go offline and you just might get the whole lot downloaded again. Of course, nothing more is downloaded if you click "Later". If you click OK you will get all your email downloaded so you can see it offline. Seems like that's what you would expect. > > > I believe the following may be an explanation for some cases, but not all. > If I choose to only download headers: > In 'Account Settings' > 'Synchronisation & Storage' > uncheck checkbox : 'Keep messages in all folders for this account on this computer' > Click on 'Advanced' button and make sure no checkboxes are selected. > > Then all emails will have the headers downloaded and I will see all emails regardless of date in online mode > So if anyone expected to only see the last 30 days then they are mistaken. Right. That's probably not clear to lots of users looking at this feature. > AND these settings..... > 'Synchronise all messages locally regardless of age' > OR > 'synchronise the most recent 30 days' > although selected...will be completely and totally ignored because synchronise is only refering to the downloading of full emails and no folders were selected under 'Advanced'. > > Surely those options should be greyed out if no folders are selected? Not sure it really matters. When you go offline, tb has to download **all** the emails regardless of age for them to be read by the user and so it mirrors the folder behavior that is seen when online. I haven't tried to go offline and download everything on this laptop since it has a very small SSD (chromebook running linux) so I run with no offline store. But maybe you could test this: Set to sync all regardless of age. And have no folder sync'd so no mbox files exist. Then go offline and allow everything to download. Now there should a mbox file for each folder. Then go back offline. Do the mbox files vanish or stick around? Do you get a prompt to compact your folders? (To get the prompt you may have to adjust the parameter **Compact all folders when it saves over Y MB in total** and restart tb.) After compacting (if prompted) do the mbox files vanish or at least become 0 in size? If no prompt for compact, does manually compacting (right-click) affect the mbox file? I would hope that if no folder is selected for offline use and you go offline and download them all that they will all be marked with "pending removal" so they can be compacted back to zero when you go back online. > > > > If the following is selected then all kinds of weirdness occur: > In 'Account Settings' > 'Synchronisation & Storage' > uncheck checkbox : 'Keep messages in all folders for this account on this computer' > Click on 'Advanced' button and select checkbox for eg: Inbox > So all emails will have the headers downloaded as before and I will see all emails regardless of date > But one folder - Inbox - is now selected and therefore the following options should now be enforced on that folder when going offline. > > 'Synchronise all messages locally regardless of age' > OR > 'synchronise the most recent 30 days' (I've selected this one) > whatever option is selected, it should be honoured when I go offline to synchronise specified amount in specified folder(s). > > Except that is not necessarilly the case............. > In offline mode - clicked on 'two blue screen icon' in Status bar...., (Note sometimes I get the 'alert' mentioned later on) I can see any email which I had selected to see when in previous online mode. Offline mode should mirror (look just like) online mode so you *should* see all the emails listed and be able to read the emails when in offline mode (using the now fully download mbox file). > So, if I had only checked emails dated today, then only emails dated today will be shown in offline mode. You're not seeing emails except today's when offline? > If I go back to online mode and select an email dated three months old, then in offline mode I will still see them. Sounds like the mbox file is not getting downloaded when you go offline. I see the alert too. Be sure to do the download again after you see the alert. > So any email in Inbox which was selected to view - regardless of date will be synchronised for offline viewing. > But any email in Inbox which was not selected to view in online mode - regardless of date will be not be synchronised for offline viewing. > Meaning I can see emails dated several months old but not yesterdays - assuming they were not selected to view in online mode. > So simply going offline - synchronise recent 30 days does not occur. I'm still not sure why it has synchronised emails just because I selected to view them. > This does not sound correct - something is amiss So are you saying you can't read emails when offline unless you had previously accessed/read them while online? This works OK for me when I download a single folder and then go offline (and retry the download when I see the alert). > > > However, providing at least one folder is selected in Account Settings: > In 'Account Settings' > 'Synchronisation & Storage' > uncheck checkbox : 'Keep messages in all folders for this account on this computer' > Click on 'Advanced' button and select checkbox for eg: Inbox > select 'synchronise the most recent 30 days' > clickon OK > > Then Exit Thunderbird and delete all mbox, index etc as before, then restart Thunderbird. > This will create appropriate index files and Inbox mbox file with last 30 days synchronised. > So at least that part worked under those specific procedures and only until you start to use Thunderbird. > > Then in online mode select a very old header of email to read and you will find it has been fully downloaded and stored in Inbox mbox file. > Am I completely missing something here? > Why are old emails being added to an mbox file when I have settings to only synchronise emails that are 30 days old, so oldest email allowed to be synchronised in the mbox file should be 17th June 2019. > > Emails older than 30 days old will get added to mbox file - synchronised for offline use - if downloaded headers are opened/selected to read, even when settings state 'synchronise only 30 days'. Yes, that seems to be the way it works. I couldn't find a rationale in the only bug report that documents the design. I suppose it is OK since the assumption is that you are accessing an old email, possibly with big attachments, so it can just be stored back in the mbox file for access efficiency. This can be justified since it is marked "pending removal" and when the space threshold is reached, it can be compacted out if the user wants to. The same occurs automatically for newer emails as times moves on: they get marked "pending removal" but remain in the mbox file until the next compact occurs (either manually by the user right-click or the auto-compact prompt when tb determines the potential empty space threshold has been reached). > > Can you confirm that the option: > select 'synchronise the most recent 30 days' > Only occurs ONCE when you Exit Thunderbird and delete all profile files and then restart Thunderbird. > And thereafter any selected downloaded header in that folder - older than the initial 30 day will get synchronised and added to mbox file for offline viewing. You can also just repair the folder. It will have almost the same effect as deleting the files. Yes, if you sync X days and you look at a message older than X days, it will be added to the mbox file and marked "pending removal". That's how it works. > > > The select 'synchronise the most recent 30 days' setting is only effective the once when you initially restart after accessing and deleteing files from profile. > > It does not mean nothing older than that initial 30 day date will get synchronised, because it can and does. Yes, and it's a feature and now a bug (I think) :). > > > OK..I've just gone offline using 'two blue screen icon' > Status bar message, connecting to server...Inbox downloaded all emails. > A pop up occurred - alert The operation failed because another operation is using the folder, please wait for that opration to finish and then try again. > click on OK Not sure what this alert is about. But if you see it you have to retry the download (or attempt to go offline) so the mbox files are fully downloaded via imap fetches. > Then you are finally offline. > This time instead of only seeing any email previously selected or only seeing the 30 days worth which I've just set up. > You can now read all emails regardless of date. > mbox file has just gone up to 2157KB which is total size on server. > Synchronise 30 days is not being honoured when you go offline. > > It cannot be correct to need to Exit Thunderbird and delete everything just to start Thunderbird and force it to synch 30 days. Repair of folder should work too. The mbox file being large is exactly what you want when offline. Otherwise how can you read old emails? The 30 day limit is n/a when you are offline. However, in the mbox file the messages older than 30 days should still be marked "pending removal" so when you go back on line you should see a prompt to compact all folders or right-click compact of Inbox should bring the mbox size back down. It works for me for a single folder for offline use but I can't now test it for all folders downloaded for offline due to small disk size.
Bug 1564421 Comment 11 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
** Edit: Some thing I stated below are wrong. See the next comment 12 for details** Anje, Hopefully it is now clear that if you set an account to sync X days, you still see all your emails, even those older than X days. Also, when you access (read) an email older than X days it gets stored in the mbox file but is marked "pending removal" and it will only be removed when the folder is compacted. So the mbox can still get bigger than it would be with just 30 days of email. This can be managed so you get an auto-compact prompt by setting the advanced parameter **Compact all folder when it will save over Y MB in total**. Or you can also manually select the large folder and compact it. This won't delete any messages that were not already "IMAP marked for deletion" from the server. Then you bring up issues with reading messages offline. [Edit: **wrong**] When you click the "two blue screen" icon and go offline it prompts to download all folders in all accounts or don't download (i.e., Later). If you choose to download, all your emails that are not already downloaded in all accounts and folder will be downloaded. However, the emails that are not configured to be synced in an account (older than X days) will still be downloaded. However, when stored in the mbox file they will (or should) be marked "pending removal". Now you can read all your emails in the folders of all your accounts. Regardless of the "sync X days" setting, for offline use *all* mail must be downloaded in the folder so it works the same as it did when online. Alternatively, when you want to go offline and you anticipate that you only need one or two folders to read, you can right-click on the folder(s), select them for offline (checkbox) and download only those folders (button) and then go offline and select "Later" so nothing more is downloaded. In this case, all the emails in just that/those folders(s) will have downloaded but those older than X days are marked "pending removal". (Note: if you fail to tick the **Select this folder for offline use** checkbox and just click the "Download now" button, the created mbox file seem to not have any old entries marked "pending removal". Seems like a bug.) In both offline cases, when you go back online and if the total size of messages in mboxes marked "pending removal" exceeds Y in the **Compact all folders when it saves over Y MB in total** parameter, you will be prompted to compact all the folders. Or you can always manually compact them. In the 2nd case, you should also clear the offline selection for the folders you selected for offline use so the mbox files remain empty. (In reply to Anje from comment #10) > However, you get all kinds of changes if you go into offline mode, but not perhaps the one you necessarilly expect. > Go offline and you just might get the whole lot downloaded again. Of course, nothing more is downloaded if you click "Later". If you click OK you will get all [Edit: **not all, just folders you have marked for offline storage**] your email downloaded so you can see it offline. Seems like that's what you would expect. > > > I believe the following may be an explanation for some cases, but not all. > If I choose to only download headers: > In 'Account Settings' > 'Synchronisation & Storage' > uncheck checkbox : 'Keep messages in all folders for this account on this computer' > Click on 'Advanced' button and make sure no checkboxes are selected. > > Then all emails will have the headers downloaded and I will see all emails regardless of date in online mode > So if anyone expected to only see the last 30 days then they are mistaken. Right. That's probably not clear to lots of users looking at this feature. > AND these settings..... > 'Synchronise all messages locally regardless of age' > OR > 'synchronise the most recent 30 days' > although selected...will be completely and totally ignored because synchronise is only refering to the downloading of full emails and no folders were selected under 'Advanced'. > > Surely those options should be greyed out if no folders are selected? Not sure it really matters. When you go offline, tb has to download **all** the emails regardless of age for them to be read by the user and so it mirrors the folder behavior that is seen when online. [Edit: again, I'm wrong about "all".] I haven't tried to go offline and download everything on this laptop since it has a very small SSD (chromebook running linux) so I run with no offline store [Edit: no really a problem.] But maybe you could test this [Edit: test not needed]: Set to sync all regardless of age. And have no folder sync'd so no mbox files exist. Then go offline and allow everything to download. Now there should a mbox file for each folder. Then go back offline. Do the mbox files vanish or stick around? Do you get a prompt to compact your folders? (To get the prompt you may have to adjust the parameter **Compact all folders when it saves over Y MB in total** and restart tb.) After compacting (if prompted) do the mbox files vanish or at least become 0 in size? If no prompt for compact, does manually compacting (right-click) affect the mbox file? I would hope that if no folder is selected for offline use and you go offline and download them all that they will all be marked with "pending removal" so they can be compacted back to zero when you go back online. > > > > If the following is selected then all kinds of weirdness occur: > In 'Account Settings' > 'Synchronisation & Storage' > uncheck checkbox : 'Keep messages in all folders for this account on this computer' > Click on 'Advanced' button and select checkbox for eg: Inbox > So all emails will have the headers downloaded as before and I will see all emails regardless of date > But one folder - Inbox - is now selected and therefore the following options should now be enforced on that folder when going offline. > > 'Synchronise all messages locally regardless of age' > OR > 'synchronise the most recent 30 days' (I've selected this one) > whatever option is selected, it should be honoured when I go offline to synchronise specified amount in specified folder(s). > > Except that is not necessarilly the case............. > In offline mode - clicked on 'two blue screen icon' in Status bar...., (Note sometimes I get the 'alert' mentioned later on) I can see any email which I had selected to see when in previous online mode. Offline mode should mirror (look just like) online mode so you *should* see all the emails listed and be able to read the emails when in offline mode (using the now fully download mbox file). [Edit: Just for folders selected for offline storage, not every folder.] > So, if I had only checked emails dated today, then only emails dated today will be shown in offline mode. You're not seeing emails except today's when offline? > If I go back to online mode and select an email dated three months old, then in offline mode I will still see them. Sounds like the mbox file is not getting downloaded when you go offline. I see the alert too. Be sure to do the download again after you see the alert. [Edit: I think the alert happens when you try to do something else while the download is in progress. You have to keep your hands off the keyboard until the download completes and tb goes offline.] > So any email in Inbox which was selected to view - regardless of date will be synchronised for offline viewing. > But any email in Inbox which was not selected to view in online mode - regardless of date will be not be synchronised for offline viewing. > Meaning I can see emails dated several months old but not yesterdays - assuming they were not selected to view in online mode. > So simply going offline - synchronise recent 30 days does not occur. I'm still not sure why it has synchronised emails just because I selected to view them. > This does not sound correct - something is amiss So are you saying you can't read emails when offline unless you had previously accessed/read them while online? This works OK for me when I download a single folder and then go offline (and retry the download when I see the alert). > > > However, providing at least one folder is selected in Account Settings: > In 'Account Settings' > 'Synchronisation & Storage' > uncheck checkbox : 'Keep messages in all folders for this account on this computer' > Click on 'Advanced' button and select checkbox for eg: Inbox > select 'synchronise the most recent 30 days' > clickon OK > > Then Exit Thunderbird and delete all mbox, index etc as before, then restart Thunderbird. > This will create appropriate index files and Inbox mbox file with last 30 days synchronised. > So at least that part worked under those specific procedures and only until you start to use Thunderbird. > > Then in online mode select a very old header of email to read and you will find it has been fully downloaded and stored in Inbox mbox file. > Am I completely missing something here? > Why are old emails being added to an mbox file when I have settings to only synchronise emails that are 30 days old, so oldest email allowed to be synchronised in the mbox file should be 17th June 2019. > > Emails older than 30 days old will get added to mbox file - synchronised for offline use - if downloaded headers are opened/selected to read, even when settings state 'synchronise only 30 days'. Yes, that seems to be the way it works. I couldn't find a rationale in the only bug report that documents the design. I suppose it is OK since the assumption is that you are accessing an old email, possibly with big attachments, so it can just be stored back in the mbox file for access efficiency. This can be justified since it is marked "pending removal" and when the space threshold is reached, it can be compacted out if the user wants to. The same occurs automatically for newer emails as times moves on: they get marked "pending removal" but remain in the mbox file until the next compact occurs (either manually by the user right-click or the auto-compact prompt when tb determines the potential empty space threshold has been reached). > > Can you confirm that the option: > select 'synchronise the most recent 30 days' > Only occurs ONCE when you Exit Thunderbird and delete all profile files and then restart Thunderbird. > And thereafter any selected downloaded header in that folder - older than the initial 30 day will get synchronised and added to mbox file for offline viewing. You can also just repair the folder. It will have almost the same effect as deleting the files. Yes, if you sync X days and you look at a message older than X days, it will be added to the mbox file and marked "pending removal". That's how it works. > > > The select 'synchronise the most recent 30 days' setting is only effective the once when you initially restart after accessing and deleteing files from profile. > > It does not mean nothing older than that initial 30 day date will get synchronised, because it can and does. Yes, and it's a feature and now a bug (I think) :). > > > OK..I've just gone offline using 'two blue screen icon' > Status bar message, connecting to server...Inbox downloaded all emails. > A pop up occurred - alert The operation failed because another operation is using the folder, please wait for that opration to finish and then try again. > click on OK Not sure what this alert is about. But if you see it you have to retry the download (or attempt to go offline) so the mbox files are fully downloaded via imap fetches. > Then you are finally offline. > This time instead of only seeing any email previously selected or only seeing the 30 days worth which I've just set up. > You can now read all emails regardless of date. > mbox file has just gone up to 2157KB which is total size on server. > Synchronise 30 days is not being honoured when you go offline. > > It cannot be correct to need to Exit Thunderbird and delete everything just to start Thunderbird and force it to synch 30 days. Repair of folder should work too. The mbox file being large is exactly what you want when offline. Otherwise how can you read old emails? The 30 day limit is n/a when you are offline. However, in the mbox file the messages older than 30 days should still be marked "pending removal" so when you go back on line you should see a prompt to compact all folders or right-click compact of Inbox should bring the mbox size back down. It works for me for a single folder for offline use but I can't now test it for all folders downloaded for offline due to small disk size. [Edit: I did the test on dev system as described in comment 12 below.]
**Edit: Some thing I stated below are wrong. See the next comment 12 for details** Anje, Hopefully it is now clear that if you set an account to sync X days, you still see all your emails, even those older than X days. Also, when you access (read) an email older than X days it gets stored in the mbox file but is marked "pending removal" and it will only be removed when the folder is compacted. So the mbox can still get bigger than it would be with just 30 days of email. This can be managed so you get an auto-compact prompt by setting the advanced parameter **Compact all folder when it will save over Y MB in total**. Or you can also manually select the large folder and compact it. This won't delete any messages that were not already "IMAP marked for deletion" from the server. Then you bring up issues with reading messages offline. [Edit: **wrong**] When you click the "two blue screen" icon and go offline it prompts to download all folders in all accounts or don't download (i.e., Later). If you choose to download, all your emails that are not already downloaded in all accounts and folder will be downloaded. However, the emails that are not configured to be synced in an account (older than X days) will still be downloaded. However, when stored in the mbox file they will (or should) be marked "pending removal". Now you can read all your emails in the folders of all your accounts. Regardless of the "sync X days" setting, for offline use *all* mail must be downloaded in the folder so it works the same as it did when online. Alternatively, when you want to go offline and you anticipate that you only need one or two folders to read, you can right-click on the folder(s), select them for offline (checkbox) and download only those folders (button) and then go offline and select "Later" so nothing more is downloaded. In this case, all the emails in just that/those folders(s) will have downloaded but those older than X days are marked "pending removal". (Note: if you fail to tick the **Select this folder for offline use** checkbox and just click the "Download now" button, the created mbox file seem to not have any old entries marked "pending removal". Seems like a bug.) In both offline cases, when you go back online and if the total size of messages in mboxes marked "pending removal" exceeds Y in the **Compact all folders when it saves over Y MB in total** parameter, you will be prompted to compact all the folders. Or you can always manually compact them. In the 2nd case, you should also clear the offline selection for the folders you selected for offline use so the mbox files remain empty. (In reply to Anje from comment #10) > However, you get all kinds of changes if you go into offline mode, but not perhaps the one you necessarilly expect. > Go offline and you just might get the whole lot downloaded again. Of course, nothing more is downloaded if you click "Later". If you click OK you will get all [Edit: **not all, just folders you have marked for offline storage**] your email downloaded so you can see it offline. Seems like that's what you would expect. > > > I believe the following may be an explanation for some cases, but not all. > If I choose to only download headers: > In 'Account Settings' > 'Synchronisation & Storage' > uncheck checkbox : 'Keep messages in all folders for this account on this computer' > Click on 'Advanced' button and make sure no checkboxes are selected. > > Then all emails will have the headers downloaded and I will see all emails regardless of date in online mode > So if anyone expected to only see the last 30 days then they are mistaken. Right. That's probably not clear to lots of users looking at this feature. > AND these settings..... > 'Synchronise all messages locally regardless of age' > OR > 'synchronise the most recent 30 days' > although selected...will be completely and totally ignored because synchronise is only refering to the downloading of full emails and no folders were selected under 'Advanced'. > > Surely those options should be greyed out if no folders are selected? Not sure it really matters. When you go offline, tb has to download **all** the emails regardless of age for them to be read by the user and so it mirrors the folder behavior that is seen when online. [Edit: **again, I'm wrong about "all"**.] I haven't tried to go offline and download everything on this laptop since it has a very small SSD (chromebook running linux) so I run with no offline store [Edit: **not really a problem.**] But maybe you could test this [Edit: **test not needed**]: Set to sync all regardless of age. And have no folder sync'd so no mbox files exist. Then go offline and allow everything to download. Now there should a mbox file for each folder. Then go back offline. Do the mbox files vanish or stick around? Do you get a prompt to compact your folders? (To get the prompt you may have to adjust the parameter **Compact all folders when it saves over Y MB in total** and restart tb.) After compacting (if prompted) do the mbox files vanish or at least become 0 in size? If no prompt for compact, does manually compacting (right-click) affect the mbox file? I would hope that if no folder is selected for offline use and you go offline and download them all that they will all be marked with "pending removal" so they can be compacted back to zero when you go back online. > > > > If the following is selected then all kinds of weirdness occur: > In 'Account Settings' > 'Synchronisation & Storage' > uncheck checkbox : 'Keep messages in all folders for this account on this computer' > Click on 'Advanced' button and select checkbox for eg: Inbox > So all emails will have the headers downloaded as before and I will see all emails regardless of date > But one folder - Inbox - is now selected and therefore the following options should now be enforced on that folder when going offline. > > 'Synchronise all messages locally regardless of age' > OR > 'synchronise the most recent 30 days' (I've selected this one) > whatever option is selected, it should be honoured when I go offline to synchronise specified amount in specified folder(s). > > Except that is not necessarilly the case............. > In offline mode - clicked on 'two blue screen icon' in Status bar...., (Note sometimes I get the 'alert' mentioned later on) I can see any email which I had selected to see when in previous online mode. Offline mode should mirror (look just like) online mode so you *should* see all the emails listed and be able to read the emails when in offline mode (using the now fully download mbox file). [Edit: **Just for folders selected for offline storage, not every folder.**] > So, if I had only checked emails dated today, then only emails dated today will be shown in offline mode. You're not seeing emails except today's when offline? > If I go back to online mode and select an email dated three months old, then in offline mode I will still see them. Sounds like the mbox file is not getting downloaded when you go offline. I see the alert too. Be sure to do the download again after you see the alert. [Edit: **I think the alert happens when you try to do something else while the download is in progress. You have to keep your hands off the keyboard until the download completes and tb goes offline.**] > So any email in Inbox which was selected to view - regardless of date will be synchronised for offline viewing. > But any email in Inbox which was not selected to view in online mode - regardless of date will be not be synchronised for offline viewing. > Meaning I can see emails dated several months old but not yesterdays - assuming they were not selected to view in online mode. > So simply going offline - synchronise recent 30 days does not occur. I'm still not sure why it has synchronised emails just because I selected to view them. > This does not sound correct - something is amiss So are you saying you can't read emails when offline unless you had previously accessed/read them while online? This works OK for me when I download a single folder and then go offline (and retry the download when I see the alert). > > > However, providing at least one folder is selected in Account Settings: > In 'Account Settings' > 'Synchronisation & Storage' > uncheck checkbox : 'Keep messages in all folders for this account on this computer' > Click on 'Advanced' button and select checkbox for eg: Inbox > select 'synchronise the most recent 30 days' > clickon OK > > Then Exit Thunderbird and delete all mbox, index etc as before, then restart Thunderbird. > This will create appropriate index files and Inbox mbox file with last 30 days synchronised. > So at least that part worked under those specific procedures and only until you start to use Thunderbird. > > Then in online mode select a very old header of email to read and you will find it has been fully downloaded and stored in Inbox mbox file. > Am I completely missing something here? > Why are old emails being added to an mbox file when I have settings to only synchronise emails that are 30 days old, so oldest email allowed to be synchronised in the mbox file should be 17th June 2019. > > Emails older than 30 days old will get added to mbox file - synchronised for offline use - if downloaded headers are opened/selected to read, even when settings state 'synchronise only 30 days'. Yes, that seems to be the way it works. I couldn't find a rationale in the only bug report that documents the design. I suppose it is OK since the assumption is that you are accessing an old email, possibly with big attachments, so it can just be stored back in the mbox file for access efficiency. This can be justified since it is marked "pending removal" and when the space threshold is reached, it can be compacted out if the user wants to. The same occurs automatically for newer emails as times moves on: they get marked "pending removal" but remain in the mbox file until the next compact occurs (either manually by the user right-click or the auto-compact prompt when tb determines the potential empty space threshold has been reached). > > Can you confirm that the option: > select 'synchronise the most recent 30 days' > Only occurs ONCE when you Exit Thunderbird and delete all profile files and then restart Thunderbird. > And thereafter any selected downloaded header in that folder - older than the initial 30 day will get synchronised and added to mbox file for offline viewing. You can also just repair the folder. It will have almost the same effect as deleting the files. Yes, if you sync X days and you look at a message older than X days, it will be added to the mbox file and marked "pending removal". That's how it works. > > > The select 'synchronise the most recent 30 days' setting is only effective the once when you initially restart after accessing and deleteing files from profile. > > It does not mean nothing older than that initial 30 day date will get synchronised, because it can and does. Yes, and it's a feature and now a bug (I think) :). > > > OK..I've just gone offline using 'two blue screen icon' > Status bar message, connecting to server...Inbox downloaded all emails. > A pop up occurred - alert The operation failed because another operation is using the folder, please wait for that opration to finish and then try again. > click on OK Not sure what this alert is about. But if you see it you have to retry the download (or attempt to go offline) so the mbox files are fully downloaded via imap fetches. > Then you are finally offline. > This time instead of only seeing any email previously selected or only seeing the 30 days worth which I've just set up. > You can now read all emails regardless of date. > mbox file has just gone up to 2157KB which is total size on server. > Synchronise 30 days is not being honoured when you go offline. > > It cannot be correct to need to Exit Thunderbird and delete everything just to start Thunderbird and force it to synch 30 days. Repair of folder should work too. The mbox file being large is exactly what you want when offline. Otherwise how can you read old emails? The 30 day limit is n/a when you are offline. However, in the mbox file the messages older than 30 days should still be marked "pending removal" so when you go back on line you should see a prompt to compact all folders or right-click compact of Inbox should bring the mbox size back down. It works for me for a single folder for offline use but I can't now test it for all folders downloaded for offline due to small disk size. [Edit: **I did the test on dev system as described in comment 12 below.**]