Try to start Firefox in <u>[[Safe Mode|Safe Mode]]</u> by holding down the Shift (Mac: Options) key to see if that helps. ---- Try to create a new profile as a test to check if your current profile is causing the problem. See "Creating a profile": *https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles *http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems. *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Sorry this forum is for questions asked in the English language. If you can not use English please let me know. I will then see if I can point you somewhere where Dutch is used. *You may find [https://translate.google.com/#en/nl/ translate.google] useful. I can use Firefox 44 ok on Windows 10 You may nee to try a clean install of Firefox. To do that the important point is to delete the Firefox program files. See * [[Firefox keeps crashing at startup#w_try-a-clean-install]]'''_try-a-clean-install''' **That should redirect for you to => '''[https://support.mozilla.org/nl/kb/firefox-blijft-crashen-opstarten#w_probeer-een-schone-installatie Firefox blijft crashen bij het opstarten]''' But on the redirect you will need to scroll down the document to '''Probeer een schone installatie''' If you get any error messages from Firefox please paste the error message in to your reply. Please post back to say if this helps you ? ----------- === Clean Install === Certain Firefox problems can be solved by performing a ''Clean reinstall''. This means you remove your Firefox program files and then reinstall Firefox. This process does not remove your [[Profiles - Where Firefox stores your bookmarks, passwords and other user data|Firefox profile]] data (such as bookmarks and passwords), since that information is stored in a different location. To do a clean reinstall of 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]].