Hi, try a ''Clean reinstall''. This means you remove Firefox program files and then reinstall Firefox. Please follow these steps: '''Note:''' You might want to print these steps or view them in another browser. #Download the latest Desktop version of Firefox from [https://www.mozilla.org mozilla.org] (or choose the download for your operating system and language from [https://www.mozilla.org/firefox/all/ this page]) and save the setup file to your computer. #After the download finishes, close all Firefox windows (or open the Firefox menu [[Image:New Fx Menu]] and click the close button [[Image:Close 29]]). #Delete the Firefox installation folder, which is located in one of these locations, by default: #*'''Windows:''' #**C:\Program Files\Mozilla Firefox #**C:\Program Files (x86)\Mozilla Firefox #*'''Mac:''' Delete Firefox from the Applications folder. #*'''Linux:''' If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see [[Installing Firefox on Linux]]. If you downloaded and installed the binary package from the [http://www.mozilla.org/firefox#desktop Firefox download page], simply remove the folder ''firefox'' in your home directory. #Now, go ahead and reinstall Firefox: ##Double-click the downloaded installation file and go through the steps of the installation wizard. ##Once the wizard is finished, choose to directly open Firefox after clicking the Finish button. More information about reinstalling Firefox can be found [[Troubleshoot and diagnose Firefox problems#w_5-reinstall-firefox|here]]. <b>WARNING:</b> Do not use a third party uninstaller as part of this process. Doing so could permanently delete your [[Profiles|Firefox profile]] data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. <u>These cannot be easily recovered unless they have been backed up to an external device!</u> See [[Back up and restore information in Firefox profiles]]. <!-- Starting in Firefox 31, the Firefox uninstaller no longer lets you remove user profile data.Ref: Bug 432017 and https://support.mozilla.org/kb/uninstall-firefox-from-your-computer/discuss/5279 [Fx31] Windows uninstaller will no longer offer the option to remove personal data --> Please report back to say if this helped you! Thank you.

If you try Firefox Safe Mode, it will disable hardware acceleration and add ons temporarily and you can see if these are contributing to the issue. If it was indeed hardware acceleration see the update below. Just as an update, after investigation of general hardware acceleration issues there is an update going out today that should resolve this. The new version will be 38.0.5 on beta and June 2nd*. Thank you for your patience, please do report back if there are any further issues. (*please note the update in this post for the change in release channel also subject to change)