Ventura 13.7.6: Finder Sidebar Favorites disappeared overnight; ~/Documents folder is empty.

When I logged into my iMac this morning, the Finder window had changed. Most of the folders listed in the Sidebar Favorites had disappeared, and the Documents folder icon brought up nothing. I had to navigate to the Documents folder from my user name; its size was correct but there was _nothing_ in it.

In Safe Mode, the only change to the Finder window was the appearance of (2) Tabs: my user name and the Desktop. I have never used Tabs in the Finder. The Sidebar Favorites were still missing. The ~/Documents folder size was correct and as far as I could tell, its contents had been restored.

After rebooting the iMac normally, the Finder window had not changed from the Safe Mode version but the Tabs that showed up in Safe Mode were gone. The Finder Sidebar Favorites had not been restored. The ~/Documents folder and its contents appear to be intact.

I haven’t tried to restore the Sidebar Favorites. For all I know, they will disappear again.

The iMac was sleeping from 23h last night until 07:45h this morning when I logged in. Having the contents of your Documents folder disappear overnight is about as scary as it gets. What happened? How can I prevent this from happening again?