The version 18.0.1 was fine, no any problems. Problems have started since I updated Firefox to version 18.0.2, before it was no issues with extension compatibility. Everything works except add-ons. I cannot install and/or update add-ons as well. I cannot open the page at https://addons.mozilla.org/ The page gives a message: "The connection has timed out".
Add-ons bar at the bottom of the screen seems to be working, but none of my extensions are showing next to the navigation bar. I run Firefox on the Linux Ubuntu 12.10 (32-bit), as well, and no issues.
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.
Create a new profile as a test to check if your current profile is causing the problems.
Re: None of my add ons are showing. Firefox 18.0.2, Ubuntu 12.10. Recent issue.
All of my add-ons have uninstalled. I've tried to re-install but they don't show up. Most of these didn't need restart to install. But some of my restart install disappeared too. I don't have much practical knowledge of computers. I understand that sum support for window has been withdrawn would that have anything to do with this?