How to run Firefox 3 and Firefox 4 simultaneously in Windows


  1. This tip is incomplete. Even if you create a new profile, you still can’t run both firefox versions simultaenously cause both versions will start using the newly created profile. You will also need to create a shortcut to Minefield browser with the newly created profile in this way: “C:Program FilesMinefieldfirefox.exe” -P -no-remote

    and then run Minefield (Firefox 4 beta) with this shortcut and Firefox 3 with the old profile. Only then you can run both versions simultaneously.

  2. Oops…link to shortcut got cut it is again: “C:Program FilesMinefieldfirefox.exe” -P Profilename -no-remote

  3. I think I believe Navjot. I had to return Firefox3 to Default User Profile to regain my Bookmarks and Settings.

    But I do not seem to get the link to Firefox4

  4. Oops…addons do not still work. How do I remove Firefox4 already in that Default Profile, as I link it to the new Profile.

  5. I tried the EASY way, got F3 & F4 running side-by-side. But my Bookmark & customisations were gone. It was rather a new installs.

    Where did I get it wrong?

  6. @blackwitch you should always backup the profile before trying out anything.For the time being do a system restore and you’ll get back the bookmarks and after that use Mozbackup utility to backup your firefox profile before proceeding further.

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