Windows – Start multiple Firefox (Portable) instances doesn’t work using -no-remote switch

firefoxportablewindows 10windows-10-v1709

Having a running Firefox installed, I want to start Firefox Portable downloaded from heise. On Windows I'm running FirefoxPortable.exe -no-remote which was posted here, but always get the error: Another instance of Firefox is already running. Please close all other instances of Firefox before you try to start Firefox Portable Edition.

Things I tried:

set MOZ_NO_REMOTE=1
FirefoxPortable.exe -CreateProfile test -no-remote
FirefoxPortable.exe -ProfileManager -no-remote

It's not a duplicate of this question since the author seems to start two instances of the same firefox installation (which also has the same default profile). In my case, I have a installed firefox instance (default profile folder %APPDATA%\Mozilla\Firefox\Profiles). The portable firefox seems to use the path Data\profile relative to FirefoxPortable.exe.

How can I start multiple Firefox instances? Is the -no-remote switch from the Firefox docs not working any more?

I'm using the latest portable version 65 of Firefox.

Best Answer

Method 1 - Flags

After testing this myself, the solution provided in this answer does indeed also work for two different installations of Firefox: Edit: According to OP, this doesn't work on their setup. The second method does, however.

firefox -no-remote -profile "profile_path"

So if you already have a running instance of your regular FF running and want to also open portable, you'd do

FirefoxPortable.exe -no-remote -profile "Data\profile"

Conversely, to open the regular install with portable already running, you'd do

firefox.exe -no-remote -profile "%APPDATA%\Mozilla\Firefox\Profiles"

_{(Actually, I only tested using absolute profiles and I already shut down my Windows PC. You might have to replace %APPDATA% with the actual path.)}

Method 2 - .ini

Another way to start multiple instances of FF portable is to add

AllowMultipleInstances=true

to the FirefoxPortable.ini in the same folder as the .exe (create it if it doesn't exist already) which, going by the documentation, automatically calls it using the -no-remote flag for you (Using this method does not guarantee the use of separate profiles though).

Related Solutions

Can Firefox have 2 Windows or Tabs open side by side, each for a different profile (one for work, one for personal use)? IE 8 can but can’t remember the profiles

here's a How-To-Geek Tutorial:

Use Multiple Firefox Profiles at the Same Time

Firefox – Start firefox using Another Profile, for specific file type(s)

The simplest solution is to use a batch file. The following was tested and confirmed to work with Firefox 30.0.

Associate .HTML Files With a Specific Firefox Profile

Create a batch file with something like the following -- for instance, for a web development profile called "Dev":

"C:\My Programs\FF30\firefox.exe" -P Dev -no-remote

You should omit any non-firefox command line switches in the .bat file commands (i.e. do not put in -osint -url "%1"). If you have never create a batch file, simply open a text file, type the appropriate command(s) and save. Then rename the file extension from .txt to .bat.

Assuming your are using Windows XP, navigate to My Computer and select the Tools -> Folder Options -> File Types tab. You need to change this file type association:

Firefox HTML Document

To be clear, to create a link only for actual .html files, just the first item needs to edited. Select the Advanced button, then Edit the default "open" action. Under the field marked "Application used to perform action:" paste the path to your .bat file e.g.

"C:\Documents and Settings\UserName\Desktop\Firefox.bat" "%1"

Make sure to use double quotes as above. Press OK, OK to finalize your changes.

You should, of course, copy the original entry in the field "just in case" and set it aside in case you want to reverse your changes at a later time. The basic form should be:

"C:\Path\To\Browser\firefox.exe" -osint -url "%1"