Windows 10 reached EOS (end of support) on October 14, 2025. If you are on Windows 10, see this article.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More
Lolu chungechunge lwabekwa kunqolobane. Uyacelwa ubuze umbuzo omusha uma udinga usizo.
Okugcinwe kunqolobane

iCloud calendar issues with TB 78.10.2

sfhowes replied
hamiltonjr

Since latest upgrade I have experienced instability with access to iCloud calendar. After updating any calendar item the calendar displays a warning badge and hovering over badge displays [paraphrasing] "calendar momentarily unavailable."

Restarting TB alleviates display of badge yet any attempt to update results in failure message and re-appearance of warning badge.

Creating new calendar item will create a new item (able to be viewed via separate device) yet new item does not appear in calendar view until TB is restarted.

Win10 (64-bit) Version 20H2 (OS Build 19042.985) TB Version 78.10.2 (32-bit)

TIA! John

Since latest upgrade I have experienced instability with access to iCloud calendar. After updating any calendar item the calendar displays a warning badge and hovering over badge displays [paraphrasing] "calendar momentarily unavailable." Restarting TB alleviates display of badge yet any attempt to update results in failure message and re-appearance of warning badge. Creating new calendar item will create a new item (able to be viewed via separate device) yet new item does not appear in calendar view until TB is restarted. Win10 (64-bit) Version 20H2 (OS Build 19042.985) TB Version 78.10.2 (32-bit) TIA! John

All Replies (3)

How is the calendar synced, i.e. how is it set up in TB? One method is with TbSync/Provider for CalDAV & CardDAV.

https://addons.thunderbird.net/en-us/thunderbird/addon/tbsync/

I am using the native (to TB 78.10.2) CalDAV API to connect to my iCloud calendar. This method has worked flawlessly (mostly) until recently prompting research which is how I learned that 78.10.1 was released in mid-May (around time issues began).

Thanks for reply.

I don't know if TB updates have affected CalDAV with iCloud, but I would try the add-on method. If you don't want to modify your current profile, you could try it in a separate profile created from Help/Troubleshooting, about:profiles.