Themes have disappeared
After updating to the latest version of Firefox all the themes under addons have simply disappeared, and when I click get addons the page goes into perpetual load, with the little loading circle swirling away. The themes page never loads...
Alla svar (1)
It is possible that there is a problem with the file(s) that store the extensions registry.
Delete the files extensions.* (e.g. extensions.sqlite, extensions.ini, extensions.cache) and compatibility.ini in the Firefox profile folder to reset the extensions registry.
New files will be created when required.
See "Corrupt extension files":
- http://kb.mozillazine.org/Unable_to_install_themes_or_extensions
- https://support.mozilla.org/kb/Unable+to+install+add-ons
If you see disabled, not compatible, extensions in "Tools > Add-ons > Extensions" then click the Tools button at the left side of the Search Bar (or click the "Find Updates" button in older Firefox versions) to check if there is a compatibility update available.
If this hasn't helped then also try to delete the addons.sqlite file.