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migrating profile in Firefox to new user login, help please.

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

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I am lost so request some expert help!!

I have had a few problems on my win 10 pro 64bit pc where my better half had hsd quite a few win profile logon errors. These hsve bern fixed via regedit until recently where nothing in the hive profile fixes it. (Hardware is fine and no malware just in case you wonder!) As a shortcut I have created a new logon to get the user up and running. Of course Firefox now does not have the old logon's profile available to the 'new' Windows user account.

So I have followed the instructions at https://support.mozilla.org/en-US/questions/1065938 to copy over the firefox profile files to the created user's profile folder.

But this has not worked. No history, passwords, settings etc available to the new windows account, though it looks like the files have been copied however confusingly repeating exercise does not warn about file overwriting!

How can the profile be updated to get all the passwords and settings into the new account?

Notes: Windows and FF up to date. My personal account is still fine it's just the other user account that is the problem. Cannot logon to the other 'old' account to use FF built in profile management but it should be ok in the newly created acount.

I am lost so request some expert help!! I have had a few problems on my win 10 pro 64bit pc where my better half had hsd quite a few win profile logon errors. These hsve bern fixed via regedit until recently where nothing in the hive profile fixes it. (Hardware is fine and no malware just in case you wonder!) As a shortcut I have created a new logon to get the user up and running. Of course Firefox now does not have the old logon's profile available to the 'new' Windows user account. So I have followed the instructions at https://support.mozilla.org/en-US/questions/1065938 to copy over the firefox profile files to the created user's profile folder. But this has not worked. No history, passwords, settings etc available to the new windows account, though it looks like the files have been copied however confusingly repeating exercise does not warn about file overwriting! How can the profile be updated to get all the passwords and settings into the new account? Notes: Windows and FF up to date. My personal account is still fine it's just the other user account that is the problem. Cannot logon to the other 'old' account to use FF built in profile management but it should be ok in the newly created acount.

Chosen solution

When you are ready, we can start moving parts of your old data and Copy it to the new profile.


First; open your file browser to the New profile;

Type about:support<enter> in the address bar.

Under the page logo on the left side, you will see Application Basics. Under this find Profile Folder. To its right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.

Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder

Linux: Under the page logo on the left side, you will see Application Basics. Under this find Profile Directory. To its right press the button Open Directory.


Second, open another file browser to the Old profile. You should see it on the directory "tree" in the first file browser. Right-click on that folder and select Open In New Window.


Warning ! ! Only Copy the files you are told. We will avoid anything that might cause problems. Here is the list of files;

cookies: cookies.sqlite Do not bother. Cookies will be created when you return to the website. However, you will have to log in everywhere. And you may lose any settings that websites store on your computer.

extensions(add-ons, themes): it would be better to download them fresh. If you need to remember what add-ons you had, open the extensions sub-folder and look at the .xpi files


logins.json and key3.db [v58+]key4.db : These are the password files. Copy Both !

persdict.dat : custom dictionary - words you added to the dictionary

mimeTypes.rdf [v55+]handlers.json : What to do with what type of file.

places.sqlite : History and Bookmarks.

prefs.js : Your settings. Note: If you were having problems, this could be contaminated.

cert8.db [v58+]cert9.db and possibly cert_override.txt : Stores all your security certificate settings and any SSL certificates you have imported into Firefox. If removed, the cert8.db, cert9.db file will be replaced.

search.json.mozlz4 : file stores the user-installed search engines that are available in the Firefox v47+

search.sqlite file and searchplugins folder store the search engines that are available in the Firefox Search bar before Firefox v47


Copy these files from the old to the new. You may get a message that the files already exist. Choose to over-write for each file.

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Chosen Solution

When you are ready, we can start moving parts of your old data and Copy it to the new profile.


First; open your file browser to the New profile;

Type about:support<enter> in the address bar.

Under the page logo on the left side, you will see Application Basics. Under this find Profile Folder. To its right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.

Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder

Linux: Under the page logo on the left side, you will see Application Basics. Under this find Profile Directory. To its right press the button Open Directory.


Second, open another file browser to the Old profile. You should see it on the directory "tree" in the first file browser. Right-click on that folder and select Open In New Window.


Warning ! ! Only Copy the files you are told. We will avoid anything that might cause problems. Here is the list of files;

cookies: cookies.sqlite Do not bother. Cookies will be created when you return to the website. However, you will have to log in everywhere. And you may lose any settings that websites store on your computer.

extensions(add-ons, themes): it would be better to download them fresh. If you need to remember what add-ons you had, open the extensions sub-folder and look at the .xpi files


logins.json and key3.db [v58+]key4.db : These are the password files. Copy Both !

persdict.dat : custom dictionary - words you added to the dictionary

mimeTypes.rdf [v55+]handlers.json : What to do with what type of file.

places.sqlite : History and Bookmarks.

prefs.js : Your settings. Note: If you were having problems, this could be contaminated.

cert8.db [v58+]cert9.db and possibly cert_override.txt : Stores all your security certificate settings and any SSL certificates you have imported into Firefox. If removed, the cert8.db, cert9.db file will be replaced.

search.json.mozlz4 : file stores the user-installed search engines that are available in the Firefox v47+

search.sqlite file and searchplugins folder store the search engines that are available in the Firefox Search bar before Firefox v47


Copy these files from the old to the new. You may get a message that the files already exist. Choose to over-write for each file.

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Thank you that worked well.

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Glad to help. Safe Surfing.