Finder Wants to make Changes

Finder is constantly popping up a dialog which asks for my (administrator) password. The dialog says "Finder wants to make changes - Enter your password to allow this" with text boxes for User Name and password. (see Image below)

If I enter my password, it seems to accept it and then pop up the same dialog again.

I have tried responding dozens (hundreds?) of times but without any apparent change.

I am running Big Sur (11.6) on a late 2015 iMac

I have searched for this message and found a few cases where people get it when they try to change something in the file system (such as delete a file or move a file). In these cases it seems that there is some sort of permission issue (e.g. on the trash folder). This is not my case. Whatever is causing the problem seems to be running in the background.

If I run in safe mode the problem does not occur.

I have rebooted the Mac many times

I thought the problem might be related to a Key Chain sync issue. I reset the logon key chain but that didn't work.

I thought the problem might be triggered by background processes associated with spotlight search. I changed my spotlight privacy settings to exclude various parts of the file system. Currently I have excluded my whole disk drive. (Macintosh HD). This didn't work either.

When I get the dialog, finder is pretty much unresponsive. It even stops a normal restart request. I have found that I can get a window to let restart work by first requesting the restart and then relaunching finder.

The dialog is not very helpful because it gives no indication about what change finder wants to make or the relevant objects. I can't find any log to shed more light on this. Does anyone know of a log that might help?

I've spent many hours trying to diagnose this and searching the internet for reports of similar problems. Any suggestions would be welcome.

Tony