I recently ran into a problem on my system where all the HTML document icons had been reset to the generic default icon:
Apparently, the Minefield build of Firefox had at some point corrupted this icon. I found that I was unable to change or reset the icon through the Folder Options » File Types dialog in Windows Explorer. No matter what I tried, I couldn't restore the icon, and it drove me nuts. Then I figured out what to do, thanks to this forum post at MozillaZine:
- Open RegEdit.
- Browse to the HKEY_LOCAL_MACHINE\SOFTWARE\Classes\FirefoxHTML registry branch.
- Delete the ShellEx\IconHandler registry key entry.
- Close RegEdit.
- In Windows Explorer, browse to the Documents and Settings\{username}\Local Settings\Application Data folder.
- Delete the iconcache.db file. It's hidden, so you may need to tweak your Windows Explorer settings to see it.
- Reboot.
Problem solved!