Rechercher dans l’assistance

Évitez les escroqueries à l’assistance. Nous ne vous demanderons jamais d’appeler ou d’envoyer un SMS à un numéro de téléphone ou de partager des informations personnelles. Veuillez signaler toute activité suspecte en utilisant l’option « Signaler un abus ».

En savoir plus

Suggested solutions do not work for "Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window."

  • 4 réponses
  • 13 ont ce problème
  • 1 vue
  • Dernière réponse par rambosauce

more options

I keep getting the error "Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window."

I attempted all recommended steps I could find on support (task manager, profile permission settings, etc.) and none of which worked. I even uninstalled Firefox and used other browsers for over a month. Upon reinstallation and launch I keep getting the same error. At this point I've exhausted all the advice I could find on this forum and hope I do not have to abandon Mozilla.

I keep getting the error "Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window." I attempted all recommended steps I could find on support (task manager, profile permission settings, etc.) and none of which worked. I even uninstalled Firefox and used other browsers for over a month. Upon reinstallation and launch I keep getting the same error. At this point I've exhausted all the advice I could find on this forum and hope I do not have to abandon Mozilla.

Solution choisie

Thank you both for the reply, I understand things are busy.

I am on Windows 7 and had previously tried reinstalling the newest version of Firefox.

I went a little aggressive and deleted the entire Mozilla folder in the AppData directory. Now the newest version has installed and launched with no problem :)

Reinstalling plugins is trivial to go back to using my favorite browser. Cheers!

Lire cette réponse dans son contexte 👍 0

Toutes les réponses (4)

more options

Guess it's goodbye Firefox! It was good while you worked!

more options

Sorry you never got a reply. Sometimes, we get so many requests for help, that some get lost.

What is your computer system and Firefox?

Have you updated to the current version?

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options)
key, and then starting Firefox. Is the problem still there?

more options

Did you try to delete the parent.lock file in the Firefox profile folder?

  • C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\

"AppData" (XP: Application Data; Mac: ~/Library; Linux: ~/.mozilla) is a hidden folder.


more options

Solution choisie

Thank you both for the reply, I understand things are busy.

I am on Windows 7 and had previously tried reinstalling the newest version of Firefox.

I went a little aggressive and deleted the entire Mozilla folder in the AppData directory. Now the newest version has installed and launched with no problem :)

Reinstalling plugins is trivial to go back to using my favorite browser. Cheers!