Heavy title I know… but I am trying to get Google to find this post 🙂
There is a myriad of information on the web about this problem, but nowhere I have found so far shows how to fix it with all of the above installed on your Windows 10 system.
The problem is a simple, but stupid one. Essentially, if you have too many “cloud sync” apps installed on your system, they all fight for a OS set limited space of 15 slots for icon overlays. These are the pretty icons the OS shows you when things are syncing up…
For me, the fix when I have Onedrive, Onedrive for Business & Dropbox installed was the following modification of the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellIconOverlayIdentifiers
With this edit, All of my apps appear to be showing Sync, Error, and Syncing icons without issue.
Hope it works for you too!