''mozillafreak [[#question-1076718|said]]'' <blockquote> I've just upgraded to Windows 10, and Mozilla seems to routinely crash on two conditions: 1. when I hit the X and close a window while on youtube and 2. when attempting full screen with youtube. Everything online suggests flash hardware acceleration but it appears that youtube is now using html5. Any rough ideas on how to troubleshoot? </blockquote> Hello, To find the correct solution to your problem, we need some more non-personal information from you. Please do the following: # Use ONE of these methods to open the Firefox Troubleshooting Information page: #* Click the menu button [[Image:New Fx Menu]], click on help [[Image:Help-29]] and select ''Troubleshooting Information''. #* Type '''about:support''' into the Firefox address bar and press the enter key. # At the top of the Troubleshooting Information page that comes up, you should see a button that says "Copy text to clipboard". Click it. #Now, go back to your forum post, right-click in the reply box and select '''Paste''' from the context menu (or else click inside the reply box and press the Ctrl+V keys) to paste all the information you copied into the forum post. If you need further information about the Troubleshooting information page, please read the article [[Use the Troubleshooting Information page to help fix Firefox issues]]. Thanks in advance for your help!