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Firefox Won't Open No Matter What!

  • 12 respostas
  • 1 has this problem
  • 7 views
  • Last reply by cor-el

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When I try to open Firefox in normal mode, it refuses to open no matter what! I try opening it in safe mode, but part of the dialog box shows for a split second before disappearing again. Firefox seems to only open in safe mode with networking. Somebody please tell me how to make Firefox work in normal mode.

When I try to open Firefox in normal mode, it refuses to open no matter what! I try opening it in safe mode, but part of the dialog box shows for a split second before disappearing again. Firefox seems to only open in safe mode with networking. Somebody please tell me how to make Firefox work in normal mode.

All Replies (12)

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Some problems occur when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again;

  • Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
  • Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see

Configure firewalls so that Firefox can access the Internet. {web link}

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I tried. It didn't work (

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Sounds like something is killing Firefox. You should compare what's not running in safe mode to what is running in normal mode to see what's causing the issue.

I would try the below tools to see what's running.

https://docs.microsoft.com/en-us/sysinternals/downloads/autoruns - To see what's running in normal mode https://docs.microsoft.com/en-us/sysinternals/downloads/process-explorer

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Oh, and I tried doing a clean boot. Firefox worked for a few seconds, but then it closed instantly :(.

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I'll try those tools you listed below, jonzn4SUSE.

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You can check for issues caused by a corrupted or incomplete Visual C++ installation that is missing runtime components (Redistributable Packages) required by Firefox, especially VCRUNTIME140_1.dll.

See "Visual Studio 2015, 2017 and 2019":

You may not need the latter (32-bit version) if you use 64-bit Firefox. You may have to reboot the computer.

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I'm not missing that file. Look at this photo of file explorer search.

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Did you install both files? Reboot?

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Oh and my problems started after installing an older version of Firefox.

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The screenshot the DLL file in the system32 folder, so that is the 32-bit version. 64 Bit Firefox need s the 64-bit VCRUNTIME140_1.dll version, so you can still try to reinstall VC runtime files.

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Do I have to delete vcruntime140_1.dll, or reinstall Visual C++ runtime?



P.S. Here's a screenshot of the file mentioned above in the system32 folder.

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You can just reinstall the two Redistributable Packages (64-bit and 32-bit) like I posted above.

Do you also see this DLL file in the system folder used by 64-bit applications as you likely use a 64-bit Firefox version ?