We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

transfer settings from one machine to another

  • 3 balasan
  • 1 ada masalah ini
  • 13 paparan
  • Balasan terakhir oleh cor-el

more options

My previous computer would not boot anymore because windows got corrupted. Instead of installing windows again on an old computer I built a new computer. I copy the Firefox related folders from my AppData folder in the old drive and copied them to the new computer's AppData. I thought that would allow me to maintain bookmarks, saved passwords to commonly used websites, and other settings but it did not. How do I get my old settings to work on the new machine?

Thanks, Carl

My previous computer would not boot anymore because windows got corrupted. Instead of installing windows again on an old computer I built a new computer. I copy the Firefox related folders from my AppData folder in the old drive and copied them to the new computer's AppData. I thought that would allow me to maintain bookmarks, saved passwords to commonly used websites, and other settings but it did not. How do I get my old settings to work on the new machine? Thanks, Carl

All Replies (3)

more options

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.


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.

more options

Hi Fred,

I am not understanding your instructions....

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.


Can you elaborate?

more options

Note that Firefox uses two locations for the Firefox profile folder, so make sure to look in the correct location.

Location used for the main profile that keeps your personal data (Root Directory on about:profiles).

  • C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\

Location used for the disk cache and other temporary files (Local Directory on about:profiles) (no need to restore profiles stored here).

  • C:\Users\<user>\AppData\Local\Mozilla\Firefox\Profiles\<profile>\