Missing TortoiseSVN icons

Can't see your TortoiseSVN icons (i.e. the green/red/other icons that decorate files and folders in Windows explorer)?

These icons are called shell icon overlays and are configured in the registry using shell icon overlay identifiers. The registry path is:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellIconOverlayIdentifiers

Windows supports a maximum of 15 such identifiers, so applications using overlays are competing for a limited resource. Vendors often approach this by prefixing their identifier keys with numbers or spaces to bump them to the top of the list – when this happens, you might find that other apps (like TortoiseSVN) are pushed down (or even off) the bottom1). Cloud-synchronised file shares (e.g. Dropbox, Google Drive, OneDrive) are common culprits.

To get your TortoiseSVN overlays to reappear, you need to edit registry keys to get them to the top of the list. TortoiseSVN's overlay identifiers are prefixed with numbers, and you'll probably find that other entries above are prefixed with spaces. You can just remove the leading spaces from these other keys.


1)
You can define as many identifiers as you like, so this doesn't lose anything – but Windows only considers the top 15 entries.