I know this question has been asked before but I can't seem to make them work now.
I have tried rebooting.
I have tried installing latest preview release.
I have tried increasing icon cache and adding quotes around the keys:
https://martinbuberl.com/blog/tortoisegit-icons-not-showing-workaround/
I have tried changing the icon overlay settings.
They now refuse to display.
Does this help?
After none of above worked for me, I searched whole registry for {C5994560-53D9-4125-87C9-F193FC689CB2} (Value of "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellIconOverlayIdentifiers\ Tortoise1Normal")
I found a key with name "{C5994560-53D9-4125-87C9-F193FC689CB2} {0C6C4200-C589-11D0-999A-00C04FD655E1} 0xFFFF" inside HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Shell Extensions\Cached
So I decided to delete all sybkeys of registry key "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Shell Extensions\Cached" and after I restarted explorer.exe all tortoise overlays started working for me
From https://tortoisegit.org/support/faq/#ovlnotall:
The overlay handler are loaded by the order of the ASCII code. Thus you need to make sure the Tortoise* overlay handler has a high precedence to be honored. This can be achieved by prepending spaces (as seen in the screenshot there is a real war going on who has the most spaces).