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Add-ons are completely gone after update


Im running firefox on 3 computers with my macbood being the primary computer to which the two other sync to.

Recently I upgraded to ff15 but all of the add-ons have vanished from my other two computers. My macbook still has them all but the other two do not. Why aren't they syncing to the othet two computers and why did they get deleted???

Additional System Details

Installed Plug-ins

  • Displays Java applet content, or a placeholder if Java is not installed.
  • Shockwave Flash 11.3 r300
  • Speed Download Plugin. Allows downloads to be redirected to Speed Download
  • The Flip4Mac WMV Plugin allows you to view Windows Media content using QuickTime.
  • Office Live Update v1.0
  • RealPlayer Plugin
  • Musicnotes Viewer plugin 1.16.11 http://www.musicnotes.com
  • DivX Web Player version
  • DivX Content Upload Plug-In: Uploads DivX video in your browser!


  • User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:15.0) Gecko/20100101 Firefox/15.0.1

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  • Top 10 Contributor
  • Moderator
10783 solutions 97065 answers

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.

You can use this button to go to the Firefox profile folder:

  • Help > Troubleshooting Information > Profile Directory: Show Folder

New files will be created when required.

See "Corrupt extension files":

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.

Helpful Reply

Thanks for that. I tried all of what you said but no go. But during my searching around I found the reset firefox button so I hit that on my device which is cloning firefox on my mac and then re-setup the sync and voila!....all good. Had to manually reset a few things but other than that it now works like before.


samdiener 0 solutions 1 answers

I've tried both the method described and the full firefox reset. None of my add-ons are visible via Firefox at all. They are still in the folder structure in my finder, but Firefox does not see them. Any ideas about what else to try? I can do without some of them, but Zotero is essential.

1stacey 0 solutions 1 answers

I hope you can help. I have vista and developed some firefox problems so I hit the "reset firefox". My bookmarks came back after restarting my computer but my Zotero file and app has disappeared. Help is greatly appreciated!