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Firefox sometimes doesn't launch

  • 3 replies
  • 1 has this problem
  • 6 views
  • Last reply by FredMcD

MartyJames
MartyJames
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Firefox usually launches OK, but about a third of the time, it just doesn't launch at all. I can see the program running in the Task Manager, but the profile manager never appears (as it normally would) and nothing happens. If I end the Firefox process and relaunch it, it still never launches. Only a restart seems to fix it.

This has been happening for a few months now, usually when my computer has been on for a while. My system has been a little slow lately and I might have thought it was a system problem, however, Firefox is the only program that seems to have any problem launching.

I don't know if it's related, but Firefox has also been very slow connecting to websites lately, with the connection often dropping out for maybe 5 minutes at a time. I know there's nothing wrong with my actual connection because all other internet-based applications work fine and never slow down.

Firefox 91, Windows 7 x64

Firefox usually launches OK, but about a third of the time, it just doesn't launch at all. I can see the program running in the Task Manager, but the profile manager never appears (as it normally would) and nothing happens. If I end the Firefox process and relaunch it, it still never launches. Only a restart seems to fix it. This has been happening for a few months now, usually when my computer has been on for a while. My system has been a little slow lately and I might have thought it was a system problem, however, Firefox is the only program that seems to have any problem launching. I don't know if it's related, but Firefox has also been very slow connecting to websites lately, with the connection often dropping out for maybe 5 minutes at a time. I know there's nothing wrong with my actual connection because all other internet-based applications work fine and never slow down. Firefox 91, Windows 7 x64

Modified by MartyJames

All Replies (3)

FredMcD
FredMcD
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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}

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.

Install both 32-bit and 64-bit "Visual Studio 2015, 2017 and 2019" downloads, (x86: vc_redist.x86.exe and x64: vc_redist.x64.exe) from https://support.microsoft.com/help/2977003/the-latest-supported-visual-c-downloads

MartyJames
MartyJames Question owner
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Thank you sir. That is good advice, but it is not causing my particular problem as Firefox runs perfectly fine most of the time, just sometimes it doesn't.

FredMcD
FredMcD
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What were you doing at the time? surfing, watching a clip, reading something . . . .


Start Firefox using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?