Folders and sub-folders collapse unexpectedly

[LaPlume]

Outlook 2021 Pro
Windows 11 Home

I've used Outlook for decades. This problem has plagued various versions over many years, but now, it's occurring even more frequently. I have hundreds of folders and sub-folders. The View setting is Group by...Expand/Collapse default: "As last viewed."

Sometimes it happens when I am at my computer and have clicked Send/Receive All Folders. Occasionally, it happens when I'm away from the computer. Very annoying!

Is there a permanent fix?



Thanks.