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.

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

Error due to updates?

Firefox was working fine. A dialogue box appeared after an unrelated restart to say firefox was downloading updates after which I could not open firefox and got the following error: firefox.exe - Bad Image The application or DLL C:\Program Files\Mozilla Firefox\xul.dll is not a valid Windows image. Please check this against your installation diskette.

Was this due to updates? Do I really need to do a clean reinstall? How do I get my bookmarks back if I do?

This happened

Every time Firefox opened

User Agent

Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)

Firefox was working fine. A dialogue box appeared after an unrelated restart to say firefox was downloading updates after which I could not open firefox and got the following error: firefox.exe - Bad Image The application or DLL C:\Program Files\Mozilla Firefox\xul.dll is not a valid Windows image. Please check this against your installation diskette. Was this due to updates? Do I really need to do a clean reinstall? How do I get my bookmarks back if I do? == This happened == Every time Firefox opened == User Agent == Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)

All Replies (1)

Might it be your hard disk is full? See this thread for possible solutions