Step 1: Press Ctrl + Shift + Esc keys at the same time to open the Task Manager. You should remember to delete all Firefox files, because only uninstalling Firefox cannot solve the issue. Therefore, the best way to fix Firefox will not open error is to reinstall the browser.
However, considering that we don’t receive any error message, it is very hard to check the exact file that causes the error. For the damaged files, the common solution is to utilize a faulty-free copy to replace them. You may be also interested in this: Windows 10 Notifications Tell Firefox Users to Use Edge Solution 1: Reinstall FirefoxĪs corrupted/damaged files are mainly responsible for Firefox won’t open Windows 10 error, you should consider reinstalling Firefox. In this case, you can remove add-ons to fix the issue. However, these add-ons may result in Firefox to misbehave as well especially when they aren’t coded well and have bugs within them.