Yesterday I accepted after an update when starting Outlook .I then received warning messages 'cannot read the calendar'. While the calendar does appear normally, When I move from Mail to calendar this warning constantly pops up.
The update is not listed in Windows update, or I would have reversed it.
Same error displays for me. Started about three weeks ago. Win10, Outlook 365/2016. When the "Cannot read the calendar" error pops up, I click it to close it and everything seems to work okay. Like others, it happens going from email (IMAP) to Calendar. Tried changing the View, outlook /safe, outlook /cleanviews, and Office REPAIR from the Control Panel Programs and Features. Eliminated Google Calendar link in Outlook. No joy. Windows System Logs are of no help. Hummmm.
WINVER 21H1 (OS BUILD 19043.906) I will check the insiders WIN10 and Office forums and also look to see if I can roll back.
Companion Link Build 9038
I don't suspect CL is the issue
Actually, I see now that the error message pops up when launching anything related to Outlook that uses/connects with the Calendar. Once I've exhausted all the combo's that make the popup pop, Outlook continues to work fine. Outlook works fine before that as well, you just have to clear the error popup.
I did not know about resetting. But have found your 'how to' now.
In complete frustration I finally performed 'System restore'. I also set a months' delay for Windows updates.
To my extreme annoyance , this morning at Outlook boot, the update announced itself, and even though I tried to close the update box. It installed and the wretched 'could not read calendar has re-appeared.
I have now printed your re-set instructions an will perform that later today
As of today, I cannot induce the "Cannot Read the Calendar" error, but, now I have a different Calendar error, "Cannot copy the items". This new error pops up in a small Window when I try to drag a Calendar item (appointment) to a new time or day on the same Calendar. I can open items and change the time or day just fine, or drag the end time and start time separately and that's okay too.
I should have said earlier that I am enrolled in the Office Insider beta program and using "Microsoft® Outlook® for Microsoft 365 MSO (16.0.14014.20002) 64-bit" and I see my WIN10 build has changed to 19043.962
So far I have tried to 1. Reset the view, 2. Quick Repair by right-clicking from Programs and Features and 3. Online Repair from Programs and Features. I couldn't and can't go back to a previous WIN10 build because it's been over ten days.
Next I will try and get out of this Insider Office build... and I will post an update if things change.
Now that I've search a bit for a solution, I see there are different errors going by the same name, or very close. I've attached a picture of what I am seeing. This occurs in Calendar only. Maybe this deserves its own thread? Unlike the earlier, "Cannot read the calendar" (now gone) error this one is limiting. I can't move my appointments as I would like.
After running a System Restore, on your advice I turned off Outlook updates (as well as Windows updates,) but it still re-appeared.
However to my surprise several days ago the problem disappeared. I note from your latest newsletter that MSoft has fixed it, but how could they do this with all my updates turned off?