Can you try to uninstall some addons?

disabled all add-ons... stilll doesn't work.. crashes everytime I restart.. works alright in safe mode though

You may already have seen this article, but just in case: Troubleshoot Firefox crashes (closing or quitting unexpectedly).

Thanks for the IDs. They mention possible graphics card issues. In Safe Mode, please try the following:

orange Firefox button or classic Tools menu > Options > Advanced

On the "General" mini-tab, uncheck the box for "Use hardware acceleration when available"

Then exit and restart Firefox in regular mode. Is the issue resolved?

See also:

• https://support.mozilla.org/kb/how-do-i-upgrade-my-graphics-drivers

Hi... Yes - this was the problem... works fine now... thanks a lot!

To be clear, I unchecked the hardware accelerator and the crashes stopped! great stuff! :)