How to Fix: Move Firefox to New Computer / Profile

Dennis Faas's picture

Infopackets Reader George F. writes:

" Dear Dennis,

I just purchased a new AMD Ryzen 1700 CPU, motherboard, and RAM for my computer - wow what a speed difference! Before I installed the new hardware I backed up all my data using Macrium Reflect. I would like to move Firefox to my new computer. I just read your article about moving Thunderbird to a new computer and was wondering if the steps are the same? "

My response:

Moving a Firefox user profile over to a new computer (or new user) is almost identical to moving over a user profile in Thunderbird, though the folder locations are different. Below I'll explain how to do that using step by step instruction.

How to Fix: Move Firefox to New Computer / Profile

  1. The first thing you need to do is locate the folder that contains your old Firefox data, then transfer it over to the new computer.

    If your old computer is still working:

    The Firefox profile folder is located %APPDATA%\Mozilla. To access this folder, go to your old computer, click Start, then type in %APPDATA% in the Start menu and press Enter. You should see a bunch of folders - look for the "Mozilla" folder; right click it and select "Copy" from the dialogue menu. Next: open My Computer (Windows XP, Vista, and 7) or My PC (Windows 8 and 10), then insert a blank USB thumb drive or DVD into the system. The drive should appear in My Computer / This PC. Once that is done, right click over top of the media you wish to use and select "Paste" from the dialogue menu. This will copy your Firefox profile folder onto the media. Eject the media when finished and place it into the new computer.

    If you've backed up the old computer using a backup program:

    You will need to manually locate the Firefox profile folder from the backup you created. For example, my Firefox profile is located in C:\Users\Dennis\AppData\Roaming\Mozilla - as such, the location of the Firefox profile folder will be similar on the backup, though the drive letter or path will be different. Note the location of the "Mozilla" folder and set it aside, as you will need to come back to this folder a little later.
  2. Download and install Mozilla Firefox if you have not already.
  3. Now it's time to copy the old Firefox profile folder over.

    If you've copied your old Firefox profile onto USB or DVD: locate the "Mozilla" folder on the media, right click it, and select "Copy" from the dialogue menu. If you're copying your old Firefox profile from a backup: go to the location of the "Mozilla" folder from within the backup, right click it, and select "Copy" from the dialogue menu.

    Next, click Start, then type in %APPDATA% and press Enter on the keyboard. The "%APPDATA%" you just entered should open a new File Explorer window and will display your AppData directory. Right click in an empty space inside the AppData folder and then select "Paste" from the dialogue menu. The "Mozilla" directory from your old Firefox profile will now be copied over.
  4. Now it's time to tell Firefox to use your old profile folder. IMPORTANT: close Firefox right now if it's open, otherwise the Profile Manager won't work. If you're using Firefox to read this right now, launch Internet Explorer, Edge, or Chrome, then copy this URL and paste it into the other browser. Once that is done, use your mouse to highlight the text below using your mouse:

    Firefox.exe -p

    Right click over top of the highlighted text above, then select "Copy" from the dialogue menu. Next, click Start, then press CTRL + V on the keyboard. The text you copied should now be output into the Start search box. Press Enter on the keyboard to execute the command.

    At this point, the Firefox Profile manager window should now appear. Click the "Create Profile" button. It will say "Welcome to the Create Profile Wizard". Click Next, then it will say "Enter new profile name". The default is "Default User" - use that, then click the "Choose Folder" button. By default, Firefox will go to the "standard" location where profiles are stored on the hard drive (which is: C:\Users\YOURNAME\AppData\Roaming\Mozilla\Firefox\Profiles).
  5. At this point you should see two folder profiles: a new one that was already created when you installed Firefox onto the new machine, and the old one that you copied over from the media. Select your old profile folder, then click the "Finish" button, then click "Exit". Launch Firefox. All your old profile data should now be moved over - pat yourself on the back for a job well done!

I hope that helps.

Additional 1-on-1 Support: From Dennis

If all of this is over your head, or if you need help moving over your old Firefox Profile onto a new computer - I can help using my remote desktop support service. Simply contact me, briefly describing the issue and I will get back to you as soon as possible.

Got a Computer Question or Problem? Ask Dennis!

I need more computer questions. If you have a computer question - or even a computer problem that needs fixing - please email me with your question so that I can write more articles like this one. I can't promise I'll respond to all the messages I receive (depending on the volume), but I'll do my best.

About the author: Dennis Faas is the owner and operator of With over 30 years of computing experience, Dennis' areas of expertise are a broad range and include PC hardware, Microsoft Windows, Linux, network administration, and virtualization. Dennis holds a Bachelors degree in Computer Science (1999) and has authored 6 books on the topics of MS Windows and PC Security. If you like the advice you received on this page, please up-vote / Like this page and share it with friends. For technical support inquiries, Dennis can be reached via Live chat online this site using the Zopim Chat service (currently located at the bottom left of the screen); optionally, you can contact Dennis through the website contact form.

Rate this article: 
Average: 4.7 (12 votes)