
I also had my TortoiseGIT shell icons quit displaying suddenly, I don't remember exactly what led up to it but I found this and tried the registry stuff changing 1TortioiseNormal to "1TortioiseNormal" and so on. I tried to create a new user on my computer, and the new user has icon overlays working just fine. \ShellIconOverlayIdentifiers, then uninstalled TortoiseGit, restarted the computer and reinstalled TortoiseGit.
I deleted all icon overlays starting with "Tortoise" in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer. Reinstall TortoiseGit (uninstall, restart, install, restart). I changed TortoiseGit settings to show different icons. In the open file dialogue of all programs, the icons still exist (!). The behaviour is, however, not like any of the others who posted questions here, because: Since that time (and I am not sure if the incident described has anything to do with it), TortoiseGit has stopped showing icon overlays in explorer. I was deleting a folder when Windows Explorer sort of crashed on me (it hung on "discovering items") for over an hour, then I restarted the system. It has been working very well for me until yesterday, when I encountered a problem.
I have been using TortoiseGit for almost a full year now.