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I cannot open Firefox or Firefox Profile Manager, even though I tried several troubleshooting steps already.

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  • 4 hawwe dit probleem
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  • Lêste antwurd fan Chris32

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Hello, My Firefox does not open at all. I tried opening it from th task bar icon, from the icon in C: Program Files (x86), I tried restarting Windows, shut my PC down and opening it again, I typed C:\Program Files (x86)\Mozilla Firefox\firefox.exe -P or C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -Profile Manager in „Windows” key + R, but nothing. I read this „If Firefox previously worked but suddenly doesn't start, it may be due to some corrupt data in your settings. Uninstalling and reinstalling Firefox would not fix this problem because your settings are not removed on uninstall. To test to see if this is the problem, use the Profile Manager to create a new profile.”, but I cannot open Profile Manager either. What else should I do? Should I uninstall and install Mozilla? I have many useful bookmarks already on it and I don’t want to lose them. I have Windows 10 Pro 64 bit on a x64-based processor. Thank you very much.

Hello, My Firefox does not open at all. I tried opening it from th task bar icon, from the icon in C: Program Files (x86), I tried restarting Windows, shut my PC down and opening it again, I typed C:\Program Files (x86)\Mozilla Firefox\firefox.exe -P or C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -Profile Manager in „Windows” key + R, but nothing. I read this „If Firefox previously worked but suddenly doesn't start, it may be due to some corrupt data in your settings. Uninstalling and reinstalling Firefox would not fix this problem because your settings are not removed on uninstall. To test to see if this is the problem, use the Profile Manager to create a new profile.”, but I cannot open Profile Manager either. What else should I do? Should I uninstall and install Mozilla? I have many useful bookmarks already on it and I don’t want to lose them. I have Windows 10 Pro 64 bit on a x64-based processor. Thank you very much.

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Hi, hold down the Shift key when you start Firefox to start in Safe Mode. More - Diagnose Firefox issues using Troubleshoot Mode.

If it works in Safe Mode, disable any theme or add-ons you have - 3-bar menu > Add-ons > Themes/Extensions and restart Firefox; then if it's OK, re-enable them one by one until you find the culprit. You may need to restart Firefox after enabling some add-ons.


Temporarily disable any security/anti-virus programs, and see if it starts.


Try a Clean Reinstall; this means you remove your Firefox program files and then reinstall Firefox. This process does not remove your Firefox profile data (such as bookmarks and passwords), since that information is stored in a different location. With Firefox closed, use another browser to download Firefox from https://www.mozilla.org/en-US/firefox/all/ and save the file to somewhere convenient on your computer.

Now delete the Firefox installation folder which should be in one of the following locations -

C:\Program Files\Mozilla Firefox C:\Program Files (x86)\Mozilla Firefox

You can now double click the file you previously downloaded to install Firefox.

If your question is resolved by this or another answer, please take a minute to let us know. Thank you!

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Hi Scribe, Thank you for your help, I didn’t manage to open Firefox neither normally nor in safe mode, not even after turning antivirus and firewall off. I tried the reinstall, I didn’t understand why you mentioned to delete the installation folder, but finally I did what I didn’t want to do, being afraid I might lose all my bookmarks (and I have many of them): I uninstalled it from Control panel – Programs and features, then I downloaded and installed it from the link you provided and then I was pleasantly surprised to see that all my bookmarks had been successfully imported when Firefox finally opened, then it asked me if I wanted to refresh it for a better performance, I let it refresh and now it’s all working fine. Thanks a lot for your help, I appreciate it.