Hello coconut11, can you replicate the issue when you click the 3-bar menu and then click exit ?

thank you

Since everything is in firefox profile which needs to be unlocked at time of opening of firefox. Do following steps which helps to you to solve this problem:

• Open Task Manager by right click on empty side of taskbar(located in bottom generally of windows) or press CTRL+SHIFT+ESC .
• Now click on Process tab and search for firefox.exe .
• Right click on that and choose End Process with Yes when asked by Task manager.
• delete all firefox.exe file from process if any other are existed there.
• now run firefox normally.

Again, if the above not works then try to Remove profile lock :

• Restart windows and not start your firefox after that.
• Go to Firefox Profile folder https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data#w_finding-your-profile-without-opening-firefox
• Delete the parent.lock file.

now run firefox.

Do you have the Firefox icon on your quick launch? Right click on it, and select Open New Window. Sometimes this works. If it opens, close it by Menu > File > Exit.

This is not a cure but will make it easier if Firefox locks up in Windows. https://support.mozilla.org/questions/997866 {web link}

Start Firefox in Safe Mode {web link} While you are in safe mode;

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select General. Look for and turn off Use Hardware Acceleration.

Poke around safe web sites. Are there any problems?