Open Bug 1713625 Opened 5 months ago Updated 2 months ago

offline support for CALDAV-calendar not working correctly


(Calendar :: Provider: CalDAV, defect)

Thunderbird 78


(Not tracked)



(Reporter: ma15d57, Unassigned)


User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:88.0) Gecko/20100101 Firefox/88.0

Steps to reproduce:

When I create a new calendar-entry (CALDAV) inside thunderbird on my desktop-computer, everthing is fine. Thunderbird synchronizes all server-entries when a network-connection is established to the CALDAV-server (e.g. Nextcloud).

When I do the same on my Notebook with enabled "offline-support" for this calendar, thunderbird synchronizes also all server-entries from the CALDAV-server.

But after a few time the synchronization doesn't work... we get no error-report,.. but not all (new) calender-entries from the CALDAV-server are shown.
The only (really not good) solution is:
1.) verify that the network-connection to the CALDAV-server is established
2.) disable the "offline-support" for this calendar
3.) start manual synchronization
4.) enable the "offline-support" for this calendar

Unfortunately, I cannot ensure that I always have a network connection (for the notebook), so permanently deactivating offline support (as with my desktop pc) is not a solution.

Actual results:

After a few time the offline-synchronization of CALDAV-calendars doesn't work... without any error-report,...
Not all (new) calender-entries from the CALDAV-server are shown.

Expected results:

The start of a (manual) complete synchronization should also do exactly just that.

PS: Many users in several inzternet-forums describes exactly this wrong behavior...


we've found another (quick-and-very-dirty) hack for solve this problem temporarily:
1.) close 'thunderbird'
2.) wait for the process to finish
3.) delete the complete calendar-cache-folder;
e.g. 'C:\Users\<username>\AppData\Roaming\Thunderbird\Profiles\<profilename>.default\calendar-data'
4.) open/start 'thunderbird'

Hopefully, someone can found another (good) solution :-)

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