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After installing new Add-on,Firefox want me to restart to complete add-on installing,but when I restart firefox,add-on dissapears from Add-ons manager and won't install

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  • 5 have this problem
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  • Last reply by cor-el

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After installing add-on,when Firefox ask me to restart to complete installation,in extensions folder it creates staged folder,but when i restart,this folder will removed and add-on not installed. The Problem first happened when some extensions would not uninstalled and Firefox keep saying that addon will be uninstalled after restart,but nothing happen after restart. So with following this instruction: http://support.mozilla.com/en-US/kb/Cannot%20uninstall%20an%20add-on After safe mode not worked either,I uninstalled extension with their IDs manually.After that I cannot install any add-on that needs restart.

After installing add-on,when Firefox ask me to restart to complete installation,in extensions folder it creates staged folder,but when i restart,this folder will removed and add-on not installed. The Problem first happened when some extensions would not uninstalled and Firefox keep saying that addon will be uninstalled after restart,but nothing happen after restart. So with following this instruction: http://support.mozilla.com/en-US/kb/Cannot%20uninstall%20an%20add-on After safe mode not worked either,I uninstalled extension with their IDs manually.After that I cannot install any add-on that needs restart.

All Replies (5)

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This can be caused if one of the files that stores details of installed extensions is corrupt.

  1. Open your profile folder, for details of how to find it see https://support.mozilla.com/kb/Profiles
  2. Close Firefox
  3. Delete the following files if they exist, extensions.cache, extensions.rdf, extensions.ini and extensions.sqlite
  4. Re-start Firefox, it will then rebuild the list on installed extensions
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Thanks for replying, But the problem still exists. (except extensions.cache other files existed and I deleted them all) Unfortunately now Firefox wrongly marked two of my extensions as incompatible with firefox 4.0.1! I may reinstall Firefox itself,but I'm afraid of having trouble after a new fresh install

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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 do a compatibility check or see if there is an update.

See also:

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Thanks cor-el,the compatibility problem solved,any idea about main problem? I can't install any new extension.

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Maybe one of the other extensions is preventing it.
You can try to install the extension in Save mode.

See also: