hi eszi, can you test if this problem is reproducible when you install firefox 37?: https://www.mozilla.org/firefox/channel/#beta

Hi philipp, yes, it's the same; the newest crash id is bp-2214c7ba-2e67-4b5c-9df7-38cdd2150303

thanks, i've filed bug 1138868 about the issue & hopefully someone from mozilla's developer team can look into it.

another questions since a few comments on these crashes suggest that it may be account specific - are you running firefox as an administrator or a normal user?

I'm just a normal user

according to a mozilla engineer looking into the crash reports more closely, this is most probably caused by external software (probably adware) hooking into the browser.

so please try to go to the windows control panel / programs and remove all potentially unwanted software and suspicious entries - toolbars, things that you have not installed intentionally, don't know what purpose they serve, etc. since this kind of crash appears to happen primarily to german speaking users, look out especially for software targeted to the german market (similar issues in the past were caused by a program called "Gutschein-Filter" for example).

afterwards, run a full scan of your system with different security tools like the free version of malwarebytes & adwcleaner, which are specialised in adware and browser hijackers. Troubleshoot Firefox issues caused by malware

in case you can solve the issue that way it would be very helpful if you could report back what caused it or with the scanlogs of those security tools so other affected users researching the issue will know what to look for.

Hi there, I did what you told me to - without any changes. Today, after one night, Firefox started normally the first time I clicked on the icon but when I closed the window and tried doing the same thing one more time - same problem again: It won't start.

Try in Windows safe mode.