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Firefox won't start after updating Win 10 Pro to version 20H2

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  • Igcine ukuphendulwa ngu hrk1

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I updated Win 10 Pro to version 20H2 and now Firefox will not start. No error message; no appearance in Task Manager. Here's what I've tried to no avail:

1) Uninstalled and reinstalled Firefox several times, including manually removing all remaining Firefox files (including my profile folder) after uninstall.

2) Tried to start Firefox with administrative privileges.

3) Clean booted Windows and tried to start.

4) Turned off Windows Firewall and tried to start.

5) Tried to start in Windows Safe Mode.

6) Extensive Google searches to try to find a solution.

Oddly, Microsoft Edge will not start either, but Chrome starts and works normally.

This is but one example of why I have held off as long as possible from doing major Windows updates over the decades that I've used Windows.

I updated Win 10 Pro to version 20H2 and now Firefox will not start. No error message; no appearance in Task Manager. Here's what I've tried to no avail: 1) Uninstalled and reinstalled Firefox several times, including manually removing all remaining Firefox files (including my profile folder) after uninstall. 2) Tried to start Firefox with administrative privileges. 3) Clean booted Windows and tried to start. 4) Turned off Windows Firewall and tried to start. 5) Tried to start in Windows Safe Mode. 6) Extensive Google searches to try to find a solution. Oddly, Microsoft Edge will not start either, but Chrome starts and works normally. This is but one example of why I have held off as long as possible from doing major Windows updates over the decades that I've used Windows.

Isisombululo esikhethiwe

It turned out that the 64-bit version of Firefox, which was downloading by default from Mozilla, won't run in my 64-bit Win 10 version 20H2, but the 32-bit version of Firefox runs. I occasionally had that kind of problem YEARS AGO with certain software, including Microsoft's own Office programs. Sad that this is still happening in 2021. This kind of annoyance is why Bill Gates probably uses Macs.

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All Replies (4)

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Also, Firefox will start and run normally when installed into a Windows Sandbox on the same computer that won't start Firefox in Win 10 version 20H2.

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We're sorry to hear that your Firefox seems to be crashing when you open it. Please perform the following steps to give us a crash report ID that helps us find out more about the cause of the crash.

  1. On the keyboard, press [Windows] The image "Windows key" does not exist. + [R]. This should bring up a Run window that contains a text field.
  2. In that text field, type %APPDATA% and press Enter. An explorer window should open.
  3. From that explorer window, double-click on the Mozilla folder, then double-click on Firefox and then on Crash reports. Double-click on submitted.
  4. Now, you should see a list of files that contain reports. Go to View > Arrange Icons by > Modified to get the most recent files at the top of the window.
  5. Open the most recent 5 files with a text editor and copy the IDs.
  6. Paste each ID with bp- into the reply window on the forums.

Thanks in advance!

You can find more information and troubleshooting steps in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

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There is no Mozilla folder in the AppData/Roaming folder.

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Isisombululo Esikhethiwe

It turned out that the 64-bit version of Firefox, which was downloading by default from Mozilla, won't run in my 64-bit Win 10 version 20H2, but the 32-bit version of Firefox runs. I occasionally had that kind of problem YEARS AGO with certain software, including Microsoft's own Office programs. Sad that this is still happening in 2021. This kind of annoyance is why Bill Gates probably uses Macs.