vanished addon icons from toolbar
how to bring back vanished addon icons
It’s possible that there is a problem with the file(s) that store the extensions registry.
Type about:support in the address bar and press enter.
Under the page logo on the left side, you will see Application Basics. Under this find Profile Folder. To its right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.
Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
Linux: Under the page logo on the left side, you will see Application Basics. Under this find Profile Directory. To its right press the button Open Directory.
Delete all extensions* files and compatibility.ini in the Firefox profile folder to reset the extensions registry.
New files will be created when required.
After, restart Firefox.
See "Corrupt extension files":
+++++++++++++++++++++++++++ You will have to approve the updating one last time.