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I am stuck on v7.0.1 of Firefox on Windows 7 because each time it restarts it gets the following error:

The update could not be installed. Please make sure there are no other copies of
Firefox running on your computer, and then restart Firefox to try again.

What got leaked that Firefox thinks it is already running when it is not. Restart of computer does not help. Is there some file I can manually delete to correct this and allow the installation to proceed?

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up vote 1 down vote accepted

I think in a case like this, I would just reinstall Firefox instead of trying to track down the true source of the problem. Simply uninstall 7, and go to and download the newest version of Firefox and install. You can back up bookmarks and such prior to doing this.

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I would check task manager in case there is an instance running that you did not know about, (at the very extreme, it could be malware).

If there isn't anything running, I recommend just downloading the latest version from the website, uninstalling full (perhaps in safe mode... may want to try an update there first!). and then installing the latest version from scratch.

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Run Firefox as administrator. That helped me in a case where other suggestions for this issue didn't help.

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