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.

Learn More

Wo archive tread sia. Meɖekuku bia biabia yeye ne ehia kpeɖeŋu.

Firefox won't open except on brand-new profile

  • 2 ŋuɖoɖowo
  • 2 masɔmasɔ sia le wosi
  • 23 views
  • Nuɖoɖo mlɔetɔ Perey

Perey
Perey
more options

Version/Platform: Firefox 43.0.3 on Windows 10 Home.

Firefox won't start, giving no error message or any other indication of activity, except that the process turns up in Task Manager. Killing the task and trying again has no effect.

Starting safe mode from the command line fails. 

   C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -safe-mode

However, creating a new profile worked. 

   C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -CreateProfile Test1
   C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -P Test1

But then I closed Firefox in order to restart it with Profile Manager (intending to follow these instructions: https://support.mozilla.org/en-US/kb/firefox-wont-start-find-solutions#w_firefox-previously-worked). Profile Manager didn't open, and neither would it start normally with the profile just created. 

   C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -profilemanager
   C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -P Test1

I had to create a new one to get it to open. 

   C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -CreateProfile Test2
   C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -P Test2
Version/Platform: Firefox 43.0.3 on Windows 10 Home. Firefox won't start, giving no error message or any other indication of activity, except that the process turns up in Task Manager. Killing the task and trying again has no effect. Starting safe mode from the command line fails. C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -safe-mode However, creating a new profile worked. C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -CreateProfile Test1 C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -P Test1 But then I closed Firefox in order to restart it with Profile Manager (intending to follow these instructions: https://support.mozilla.org/en-US/kb/firefox-wont-start-find-solutions#w_firefox-previously-worked). Profile Manager didn't open, and neither would it start normally with the profile just created. C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -profilemanager C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -P Test1 I had to create a new one to get it to open. C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -CreateProfile Test2 C:\Users\****>"C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -P Test2

All Replies (2)

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

Try to rename AppData\Roaming\Mozilla\Firefox and AppData\Local\Mozilla\Firefox folder in case there is a problem with the permissions or with security software.

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

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) to see if that helps.

Perey
Perey Biabia la
more options

It complicates matters that the problem appears to be intermittent: sometimes Firefox starts just fine. However, if it doesn't work, it's guaranteed to continue not working until after rebooting (at least once).

I encountered no problems renaming the AppData folders. Booting into Safe Mode seems to allow Firefox to start reliably.

I'm wondering whether this is related to some OEM garbage preloaded on this new Acer laptop; I cleared off several items, but there's still more (and information on what they're for seems to be lacking online).