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Firefox has stopped working message immediately after trying to launch

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  • 1 has this problem
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  • Last reply by kathpbrown

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This has just started. I'm not aware that I've changed anything on the PC (Windows 8). The message appears a couple of times on each startup attempt. I've uninstalled and reinstalled. I tried the refresh and Shift click to get into safe mode. There has been no change to the error. I can access other websites and Microsoft Edge is working OK.

This has just started. I'm not aware that I've changed anything on the PC (Windows 8). The message appears a couple of times on each startup attempt. I've uninstalled and reinstalled. I tried the refresh and Shift click to get into safe mode. There has been no change to the error. I can access other websites and Microsoft Edge is working OK.

Chosen solution

See:

If you have an "Old Firefox Data" folder on the desktop because you used the Refresh feature in Firefox then you can possibly restore the bookmark from a backup in the bookmarkbackups folder.


You can copy certain files with Firefox closed to the current profile folder to transfer or recover personal data. Note that best is to avoid copying a full profile folder.


  • bookmarks and history: places.sqlite
  • favicons: favicons.sqlite
  • bookmark backups: compressed .jsonlz4 JSON backups in the bookmarkbackups folder
  • cookies.sqlite for the Cookies
  • formhistory.sqlite for saved autocomplete Form Data
  • logins.json (encrypted logins;32+) and key4.db (decryption key;58+) for Passwords saved in the Password Manager
    key3.db support ended in 73+; to use key3.db in 58-72, make sure to remove key4.db
  • cert9.db (58+) for (intermediate) certificates stored in the Certificate Manager
  • persdict.dat for words added to the spell checker dictionary
  • permissions.sqlite for Permissions and possibly content-prefs.sqlite for other website specific data (Site Preferences)
  • sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder)

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

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places.sqlite has done it! Thanks so much. And good tip about not copying the whole Profile folder, but I'd already done that. I'll know for next time.

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