As of yesterday (9th December 2025), Microsoft have released a new mainstream patch as part of its Super Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033). Fixed mainstream builds will be at least 26100.7462 (24H2) or 26200.7462 (25H2). Technically, anything after preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Bug 1998531 Comment 38 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
As of yesterday, Microsoft have released a new mainstream patch as part of its Super Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033). Fixed mainstream builds will be at least 26100.7462 (24H2) or 26200.7462 (25H2). Technically, anything after preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
As of yesterday, Microsoft have released a new mainstream patch as part of its Super Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033). Fixed mainstream builds will be at least 26100.7462 (24H2) or 26200.7462 (25H2). Technically, anything after preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
As of yesterday, Microsoft have released a new mainstream patch as part of its Super Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033). Fixed mainstream builds will be at least 26100.7462 (24H2) or 26200.7462 (25H2). Technically, anything after preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream patch as part of its Super Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033). Fixed mainstream builds will be at least 26100.7462 (24H2) or 26200.7462 (25H2). Technically, anything after preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its Super Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033). Fixed mainstream builds will be at least 26100.7462 (24H2) or 26200.7462 (25H2). Technically, anything after preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December Super Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033). Fixed mainstream builds will be at least 26100.7462 (24H2) or 26200.7462 (25H2). Technically, anything after preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December Super Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically, anything after preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically, anything after preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird freezing issues (believed when using an external monitor) on prior build versions starting from xxxxx.6725. Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform (OS build based feature toggles and the like) then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird freezing issues (believed when using an external monitor) on prior build versions starting from xxxxx.6725. Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform (OS build based feature toggles and the like) then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird freezing issues (believed when using an external monitor) on prior build versions starting from 26100.6725 (24H2) or 26200.6725 (25H2). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform (OS build based feature toggles and the like) then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird freezing issues (believed when using secondary monitors) on prior build versions starting from 26100.6725 (24H2) or 26200.6725 (25H2). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build => XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform (OS build based feature toggles and the like) then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird freezing issues (believed when using secondary monitors) on prior build versions starting from 26100.6725 (24H2) or 26200.6725 (25H2). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform (OS build based feature toggles / timeouts and the like) then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird freezing issues (believed when using secondary monitors) on prior build versions starting from 26100.6725 (24H2) or 26200.6725 (25H2). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform (OS build based feature toggles / API thread timeouts and the like) then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird freezing issues (believed when using secondary monitors) on prior build versions starting from 26100.6725 (24H2) or 26200.6725 (25H2). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build XXXXX.7309 will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform (OS build based feature toggles / API thread timeouts and the like) then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird freezing issues (believed when using secondary monitors) on prior build versions starting from 26100.6725 (24H2) or 26200.6725 (25H2). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build 26100.7309 (24H2) or 26200.7309 (25H2) will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December 2025 Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline further, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform (OS build based feature toggles / API thread timeouts and the like) then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird freezing issues (believed when using secondary monitors) on prior build versions starting from 26100.6725 (24H2) or 26200.6725 (25H2). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build 26100.7309 (24H2) or 26200.7309 (25H2) will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December 2025 Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform (OS build based feature toggles / API thread timeouts and the like) then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird freezing issues (believed when using secondary monitors) on prior build versions starting from 26100.6725 (24H2) or 26200.6725 (25H2). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build 26100.7309 (24H2) or 26200.7309 (25H2) will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December 2025 Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform (OS build based feature toggles / API thread timeouts and the like) then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird notification triggered freezing issues (believed when using secondary monitors) on prior build versions starting from 26100.6725 (24H2) or 26200.6725 (25H2). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build 26100.7309 (24H2) or 26200.7309 (25H2) will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December 2025 Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform (OS build based feature toggles / API thread timeouts and the like) then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird notification triggered freezing issues (believed to exhibit when using secondary monitors) on prior build versions starting from 26100.6725 (24H2) or 26200.6725 (25H2). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build 26100.7309 (24H2) or 26200.7309 (25H2) will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.
Microsoft have, as of yesterday, released a new mainstream Windows 11 patch as part of its December 2025 Patch Tuesday, [December 9, 2025—KB5072033 (OS Builds 26200.7462 and 26100.7462)](https://support.microsoft.com/en-gb/topic/december-9-2025-kb5072033-os-builds-26200-7462-and-26100-7462-0c1a4334-19ba-406d-bb1e-88fcffc87b79): > This security update contains fixes and quality improvements from KB5070311 (released December 1, 2025) I have had no Windows Notification issues (and therefore no Mozilla Firefox or Thunderbird notification issues) since deploying the preview December 1st patch. Therefore if the reported crashes start to decline, unless there's any outstanding "in case this happens again" future mitigation planning activity Mozilla wishes to perform (OS build based feature toggles / API thread timeouts and the like) then I am happy for Mozilla to close this bug at its discretion. End users can either simply use Windows Update or manually install [KB5072033](https://www.catalog.update.microsoft.com/Search.aspx?q=KB5072033) to fix any Firefox and Thunderbird notification triggered freezing issues (believed to exhibit when using secondary monitors) on prior build versions starting from 26100.6725 (24H2) or 26200.6725 (25H2). Fixed mainstream build version numbers will be greater than or at least equal to 26100.7462 (24H2) or 26200.7462 (25H2). Technically though, any build after the preview release build 26100.7309 (24H2) or 26200.7309 (25H2) will also be fine. Thank you for your time and patience reading about my problems with Thunderbird.