I had an issue with my 2013 Mac Pro and wound up having to wipe my drive and do a fresh Big Sur install. Was able to do a TM restore for one user (my wife) but couldn't restore my user. Not really an issue since I keep everything in DB. Once I had everything restored. I ran DB (latest version 117.4.378). I was able to sync my wife's DB and all seemed fine, except that her DB Documents folder would not display the items in the finder, well partially. I could see them in list view, but could not see them when in column or icon view or if I was in the folder, directly. I could see all of the items in Terminal, no problem. I could even launch and open documents, but they would not display. I could even open documents from within an app like Word, for instance. I eventually solved that problem, by turning off selective-syncing of the Documents folder and then re-enabled selective-sync, switched Smart Sync to local and all of the items show up in Finder now.
So now I am setting up my user, as a new Mac user. DB is syncing all of my items and I can see all of my folders and items, except now my Documents folder is having the same issue. I have tried the same trick as before with no luck. I can see all of my files in the Documents folder in Terminal and can open directly from within apps, and If I am at any level above the Documents folder I can turn the arrow down in List View to see all of the files in the Documents folder (all have a green checkmark), but cannot see them if I open a Finder window directly in the Documents folder (it just looks like an empty folder).
I can also create items from Terminal (mkdir, touch, etc.) or from within apps directly (like Word) in the Documents folder, I can also drag items into the Documents folder in the finder in List View when sitting above that folder but not while sitting inside the folder itself. If I try to drag anything into it with the focus on the Documents folder, it acts like a locked folder (it isn't locked according to GetInfo). If I try to create a create a folder while sitting inside of the Documents folder, I get an error, The Operation Can't Be Completed: An Unexpected Error Occurred (error code -43) - looked that up and doesn't seem to help much here.
I am hoping someone else out there has experienced this and has a fix.
Thanks. OK, after a bit more searching around, I believe I figured out what was going on.
My system had previously had the OS upgraded over the years and I had not done a fresh install in many, many years. So I think some of the more recent changes in Catalina/Big Sur may not have presented themselves before this new fresh install.
I think there was an issue between iCloud Drive, Dropbox's new Backup option and how symlinks now work under Mac OS 11. I had for years, had my Mac user Documents folder symlinked into my DB Teams account Documents folder. Ultimately, I had to turn off iCloud Drive (I don't really use it anyway), disable the Dropbox backup option (even though I had deselected the Documents folder, so this should not have affected this) and then signed out of DB to unlink my system from DB. After that, I could see all of the Documents in the Finder, no issue. I had to create the symlink to my DB Documents folder (followed new steps I found here ), then signed into DB again and all seems to be working, and I have also enabled one folder for backup in DB as well.
I have not tried re-enablingiCloud drive either at this point.
If anyone has a similar issue, this may be the solution.