I just synched Drobox between my old Windows 10 laptop (the source) and my new Window 11 desktop (the target). I then did a Windows Properties on the Dropbox folder on both machines.
On the source:
273,345 Files, 32,878 Folders
On the target:
273,344 Files, 32,878 Folders
So there's one less file on the target. Is there a quick and easy way for me to identify the file that wasn't synched?