This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Rohkem teavet

Teema arhiveeriti. Please ask a new question if you need help.

Firefox will not start because "A copy of Firefox is already open. Only one copy of Firefox can be open at a time".

  • 1 vastus
  • 1 on selline probleem
  • 8 views
  • Viimati vastas cor-el

dknodel2106
dknodel2106
more options

I had a major crash of Firefox - maybe virus or malware. I think computer is clean now. I deleted all Mozilla/Firefox files I could find and re-install Firefox. Will not run in safe mode (same error). Since I deleted Firefox/Mozilla files, I can not supply crash information/logs :( It runs fine on another computer on my network, this MacBookPro, same OSX and version of Firefox.

Profile Manager?

I had a major crash of Firefox - maybe virus or malware. I think computer is clean now. I deleted all Mozilla/Firefox files I could find and re-install Firefox. Will not run in safe mode (same error). Since I deleted Firefox/Mozilla files, I can not supply crash information/logs :( It runs fine on another computer on my network, this MacBookPro, same OSX and version of Firefox. Profile Manager?

All Replies (1)

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
more options

Create a new profile as a test to check if your current profile is causing the problems.

See "Basic Troubleshooting: Make a new profile":

If that new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.

See: