- Press the Windows key + R and enter regedit.
- Navigate to the following registry key with this path:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellIconOverlayIdentifiers
- Scroll right for complete command line.
- If the Dropbox overlays are in the first 15 positions, they will display; otherwise you'll need to make room for them. Please note that this requires you to delete or deprioritize other applications' overlays, so only proceed if you're sure about what you'll affect.
- If you decide to proceed, you can select individual keys and delete them by right-clicking on the desired key. If you don't want to delete them, you can rename them and place a Z at the beginning to send them to the end of the alphabetically sorted list.
- Quit explorer.exe and launch again from the Task Manager, or restart your computer.
- Launch Dropbox, and the sync icons should re-appear.
I hope this info helps, let me know what you find - thanks!