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.

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

Help can't uninstall or reinstall firefox, it worked yesterday

  • 1 reply
  • 7 have this problem
  • 3 views
  • Last reply by cor-el

more options

Woke up and for some reason when I turned on my computer firefox wouldn't work. windows said "The application has failed because its side-by-side configuration is incorrect. So I tried to unistall and reinstall the program and it wont uninstall the program.

I am running window 7 ultimate service pack 1 64 bit operating system.

It says the same thing when I try and download a new copy of firefox, I can download the program but get the same error when I try and install the download.

Please HELP I hate Internet Explorer and that is the only thing I have to use.

Woke up and for some reason when I turned on my computer firefox wouldn't work. windows said "The application has failed because its side-by-side configuration is incorrect. So I tried to unistall and reinstall the program and it wont uninstall the program. I am running window 7 ultimate service pack 1 64 bit operating system. It says the same thing when I try and download a new copy of firefox, I can download the program but get the same error when I try and install the download. Please HELP I hate Internet Explorer and that is the only thing I have to use.

All Replies (1)

more options

Seems to be caused by a corrupted Visual C++ installation (multiple versions can be installed side-by-side; SxS). You can try to use the sxstrace.exe tool to see if you can find which files are missing or corrupted and (re)install missing Visual C++ libraries.