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Firefox reports it is running but not responding.

  • 9 replies
  • 1 has this problem
  • 20 views
  • Last reply by cor-el

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In trying to use features of various apps, the app tries to connect to Firefox, resulting in an error message "Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window." But in fact, Firefox IS running. An example of this problem is invoking updates of some apps; another is in Zoom trying to login using SSO. It leaves me stuck, and the only solution I have found is to use Edge instead of Firefox.

In trying to use features of various apps, the app tries to connect to Firefox, resulting in an error message "Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window." But in fact, Firefox IS running. An example of this problem is invoking updates of some apps; another is in Zoom trying to login using SSO. It leaves me stuck, and the only solution I have found is to use Edge instead of Firefox.

All Replies (9)

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Go to about:profiles in the address bar and make sure that the active profile labeled "This is the profile in use and it cannot be deleted" is set as the default profile.

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Thanks for the suggestion. However, that profile (named Profile: default-release) is indeed indicated as the default profile.

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Are there multiple profiles listed?

Can you open a web link from an app when Firefox is not running? Does it open using the correct profile with all your settings?

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There are two other profiles listed: "Profile: default", which is NOT the default; and "Profile: App875c88d42e0d418d94ece00cb64ebc6bProfile: App875c88d42e0d418d94ece00cb64ebc6b", which is also not the default. I have no idea how they got there, as I have no recollection of ever fiddling with Firefox profiles. Do you recommend removing them?

I am reluctant to close Firefox, as I have about a dozen open tabs that are part of ongoing projects.

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There are several possible reasons for the message. This may help.

https://support.mozilla.org/en-US/kb/Firefox-already-running-not-responding

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Terry and zeroknight, thanks for your messages.

Terry, I have tried almost everything in the article you pointed me to, without success. I am in acute frustration, having spent the morning trying things suggested in that article. I think the only thing I have yet to try is creation of a replacement profile. But I'm going work on that later; right now my nerves are shot.

Thanks again for your help.

(Why does this have to be so darn complicated?!)

George Friedman

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How are you starting Firefox? Are you using the -no-remote switch in the target line of a Firefox shortcut as that makes it impossible to open an external link in this instance ?

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No, I start Firefox by clicking on the icon on my desktop, which Firefox put there when it was installed. It contains the command ""C:\Program Files\Mozilla Firefox\firefox.exe"" (no parameters).

For the record, I found an old message thread on this problem which had two suggestions: reinstall Firefox, and eliminate all profiles other than the default one I'm using. I tried each (one at a time). Neither fixed the problem.

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Did you try to remove parent.lock like mentioned in this article ?

You can create a new profile as a quick test to see if your current profile is causing the problem.

See "Creating a profile":

If the new profile works, you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.