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Profile backup problem

Firefox profile file names to long error when I try to copy my profile to an external hard drive. Firefox 67. Only option is to skip or cancel. Will the profile work when I copy it back into Firefox on another machine?

Firefox profile file names to long error when I try to copy my profile to an external hard drive. Firefox 67. Only option is to skip or cancel. Will the profile work when I copy it back into Firefox on another machine?

Chosen solution

If you copy the profile folder to an external hard drive the only copy the xxxxxxxx.default-release folder and do not use a destination folder on the external drive with a too long path.

You do not need all the files in the profile folder as restoring a full profile folder can cause issues, so best is to only copy important database and setting files.


These are basic files you can backup that are safe to transfer provided that there aren't any problems.

  • 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 (passwords) and key4.db (58+) or key3.db (57 and older) (decryption key) for Passwords saved in the Password Manager
    if you only have key3.db then make sure to remove an existing key4.db
  • cert9.db (58+) or cert8.db (57 and older) for (intermediate) certificates stored in the Certificate Manager
    if you only have cert8.db then make sure to remove an existing cert9.db
  • persdict.dat for words you added to the spelling 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)
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All Replies (3)

Some files in the profile are skipped, or the entire profile folder is skipped? You could do a compare and see what was missed.

I suspect some of the longer names could be found in the storage folder, but that's just a guess. Offline website data, add-on data, and some feature data is stored in those folders.

Also, do you get this error using Windows File Explorer or XCopy or another tool? There may be other programs that can work around this issue.

Chosen Solution

If you copy the profile folder to an external hard drive the only copy the xxxxxxxx.default-release folder and do not use a destination folder on the external drive with a too long path.

You do not need all the files in the profile folder as restoring a full profile folder can cause issues, so best is to only copy important database and setting files.


These are basic files you can backup that are safe to transfer provided that there aren't any problems.

  • 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 (passwords) and key4.db (58+) or key3.db (57 and older) (decryption key) for Passwords saved in the Password Manager
    if you only have key3.db then make sure to remove an existing key4.db
  • cert9.db (58+) or cert8.db (57 and older) for (intermediate) certificates stored in the Certificate Manager
    if you only have cert8.db then make sure to remove an existing cert9.db
  • persdict.dat for words you added to the spelling 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)

Thank you for the reply's. I have copied the relevant folders out of the profile. I am sending the unit in for warranty work. (Charging port problem.) Put a Primary Password on for now. Thanks again.