Today, in all my drives in Windows 7 appeared a red icon. I try to delete the IconCache.db but doesn’t work.
Solution:
Update: it’s caused by a change in the Windows system by the updates in combination with Dropbox. The Dropbox icon from folders is used on all devices. To fix it whithout deinstalling Dropbox I just removed the overlay icons (which I never bothered about):
Use the RegEdit to go to HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionExplorerShellIconOverlayIdentifiers
You will see a couple of ” DropboxExt0x” entries (01-10 for me). You can export a Backup from the whole “ShellIconOverlayIdentifiers” entry and then delete the Dropbox ones. After a restart the issue is fixed (for now).