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Firefox will not start

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  • 1 has this problem
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  • Last reply by FredMcD

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Firefox will not start win 10 Lenovo desktop. Have spent hours chasing through search engine responses. Seems possible I have corrupt file in profile, but have tried chasing this several ways including delete profile, uninstall then reinstall FF, etc. Any suggestions?

Chosen solution

Finally got problem solved after hours of trying the various suggestions. Finally realized that my problem was somehow linked to having both a 32- and 64-bit version of FF installed. After uninstalling the 32, the 64-bit now works normally. Unfortunately, I lost a lot of my data, but can probably restore most of it from backups that I have. Thanks for the help.

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Start Firefox in Safe Mode {web link}

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


When did this start? Any updates?


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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Problem started I think 3 or 4 days ago when I tried updating to latest version of FF. As for trying to run FF in safe mode, I haven't been able to. There seems to be 2 ways: one requires you to already be in FF in order to click on the menu button, then help, then restart with add-ons disabled. Since I can't open FF, can't use this method. The other way says to hold down shift key while starting FF. That does nothing.

I did go to Windows Firewall and found that Firefox.exe was already in the list of exceptions. So that didn't help, either.

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Start your Computer in safe mode with network support. Then start Firefox. Try Secure websites. Is the problem still there?

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

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Started PC in safe mode with network support. Attempted to start FF. Error message: "Firefox profile cannot be loaded. It may be missing or inaccessible."

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Chosen Solution

Finally got problem solved after hours of trying the various suggestions. Finally realized that my problem was somehow linked to having both a 32- and 64-bit version of FF installed. After uninstalling the 32, the 64-bit now works normally. Unfortunately, I lost a lot of my data, but can probably restore most of it from backups that I have. Thanks for the help.

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