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ppps
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Another instance of Firefox is already running

I need to run 2 separate instances of Firefox portable, because I need to login to the same online app with 2 different accounts. I have tried the addon cookiepie to manage per-tab cookies, but it has unbearable side effects.

So I installed 2 instances of firefox portable, but when I launch the 2nd instance, I get this message. What is the work around?

http://img9.imageshack.us/img9/8997/ss20100609090922.jpg

Chris Morgan
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Firefox design

That's part of Firefox's design. You can't get around it. If you allow it then it just creates a new window in the first instance.

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There is (was?) a plugin to

There is (was?) a plugin to Firefox that enabled you to switch between multiple sets of (regular) cookies in the same instance of Firefox to achieve what you want but I suspect that it was obsoleted by flash cookies. Anyway, there is a way to achieve what you want. Here's how...

Get yourself a copy of Sandboxie from sandboxie.com. There's a freebie version (which can also be portable) but the whole thing with a full, lifetime license is only $40 or so. What it does is to trap calls to the OS within 'sandboxes' allowing multiple instances of an app to run simultaneously, each contained within its own Sandbox and, depending on how you have it configured, each completely unaware of the other instances. This means you can, for example, have multiple instances of Firefox portable running simultaneously, each with its own its own cookies, history, bookmarks etc. OR each reading the same cookies history, bookmarks etc. (though obviously only one with write access). You can even specify which of these are specific to a given instance and which are common.

The full license enables you to create as many sandboxes as you like and to have Sandboxie auto-intercept app launches but you'll be able to see what it's up to with the freebie version and at least run two entirely independent instances of Firefox. Have fun!

gluxon
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It was called
Darkbee
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MultiFox

Use the add-on MultiFox.

computerfreaker
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Can't believe nobody's mentioned this yet...

pppsI installed 2 instances of firefox portable, but when I launch the 2nd instance, I get this message.

Guys, he's not just trying to switch cookies, he's trying to use multiple instances of FFP at the same time.
Here's how to do it:
1. Close all instances of Firefox Portable.
2. Copy FirefoxPortable\Other\Source\FirefoxPortable.ini to FirefoxPortable (next to FirefoxPortable.exe)
3. Open FirefoxPortable\FirefoxPortable.ini in a text editor (even Notepad will do)
4. Change "AllowMultipleInstances=false" to "AllowMultipleInstances=true" (no quotes)
5. Save FirefoxPortable.ini
6. Repeat for all other installations of Firefox Portable
7. Run multiple installations of Firefox Portable

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Chris Morgan
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No

ppps ... because I need to login to the same online app with 2 different accounts.

Cookie management should be sufficient for what has been requested.

As I mentioned above, it's part of Firefox's design. With an official version of Firefox, you can't get around it at all; if you turn on AllowMultipleInstances, it will just create a new window in the first instance. The only way you can get multiple profiles of Firefox running at the same time is when the XULRunner ID is different - for example, is you use Firefox 3.7 Alpha ("Minefield") and Firefox 3.6 ("Firefox"). Then they won't clash.

I am a Christian and a developer and moderator here.

“A soft answer turns away wrath, but a harsh word stirs up anger.” – Proverbs 15:1

sodam
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YES

Chris, for an admin, you surprisingly ignorant on this.

I use this all the time when I am developing Firefox plugins.

To set this up, do the following:

1) Copy FirefoxPortable.ini from FirefoxPortable\Other\Source to FirefoxPortable\
2) Edit FirefoxPortable.ini and change the following 2 lines:

AdditionalParameters=
to
AdditionalParameters=-no-remote

AllowMultipleInstances=false
to
AllowMultipleInstances=true

3) Run FirefoxPortable.exe any time, regardless of how many other instances of Firefox or FirefoxPortable that are running.

Caporal
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Of course you can. In the

Of course you can.

In the official version, change the link for this one.
"C:\Program Files\Mozilla Firefox\firefox.exe" --profilemanager -no-remote

I dont know how to do that on the portable version though.

ppps
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This works best for me

Thank you all for your detailed answers. Almost everything has been written, this could probably make it to the FAQ or something?

To summarize, there is no native way to run separate instances of Firefox of the same version, with different sets of cookies and different process ID. The closest way to achieve this is to use sandbox techniques. This solution is not ideal (complex to set-up, probably some performance decrease, proposed solution costs money).

An other way is to use adds on to deal with separate cookies. I tried cookie swap and cookie pie, but had issues with these 2. Finally, the solution that works for me is Multifox. This add on launches a new firefox window and treats cookies independently. It really feels like having 2 separate instances of firefox running on at the same time (although technically speaking it is only one single process).

Jimbo
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There is a way, but not a portable one

pppsTo summarize, there is no native way to run separate instances of Firefox of the same version, with different sets of cookies and different process ID.

There is a way to run more than one instance of firefox, of the same version, with separate cookies etc., but not with the same profile.

It may not be what you need, but I use it at work to be able to run both my work Firefox setup and my portable (home) one simultaneously.

How I do it is this:
in the %APPDATA%\Mozilla\Firefox\profiles.ini (this is the locally installed firefox) I have added a new profile definition

[Profile1]
Name=Portable
IsRelative=0
Path=z:\PortableApps\FirefoxPortable\Data\profile

(z:\ is always the drive letter that my papps drive gets here)

Then I can launch (local) Firefox normally for the work profile, and also launch (local) firefox.exe with the command line parameters

C:\Program Files\Mozilla Firefox\firefox.exe -no-remote -P Portable

Which makes the second instance run happily alongside the first, using the profile folder from my portable instance.

Any remote launches (clicked links from other apps etc.) will always be in my work instance, due to the -no-remote flag.

sodam
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You CAN do this natively

This functionality is built in to Firefox, it's not hard to do.

To set this up, do the following:

1) Copy FirefoxPortable.ini from FirefoxPortable\Other\Source to FirefoxPortable\
2) Edit FirefoxPortable.ini and change the following 2 lines:

AdditionalParameters=
to
AdditionalParameters=-no-remote

AllowMultipleInstances=false
to
AllowMultipleInstances=true

3) Run FirefoxPortable.exe any time, regardless of how many other instances of Firefox or FirefoxPortable that are running.

Easy, Peasy, no mess, no trouble.

This is much easier than messing with the cookies, and you can make global changes like having one session with a particular add-on, theme, extension, plugin, preference, etc...

Hope you haven't given up due to the the naysayers.

Simeon
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cool

Just tried it and it actually seems to work Smile

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John T. Haller
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Same Thing

Setting AllowMultipleInstances and AdditionalParameters=-no-remote is actually the same thing. By setting AllowMultipleInstances, it tells the launcher to allow them and it sets the environment variable MOZ_NO_REMOTE to 1, which is the same as passing -no-remote to firefox.exe (at least according to Mozilla's docs).

Scratch that... it does seem that the env var way doesn't let links be passed properly. I'll switch it to command line on next release.

Sometimes, the impossible can become possible, if you're awesome!

sodam
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Env vars

I think that the environmental variable would work on Linux and probably Macs too, but I'm pretty sure Windows doesn't use the same variable system so it doesn't recognize the switch.

ppps
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Editing FirefoxPOrtable.ini won't work

@sodam. Thank you for pointing to a very simple procedure, unfortunately it does not work.

My FirefoxPortable\FirefoxPortable.ini file looks like this: (I have just made the 2 changes you suggest)

=============== start ==================
[FirefoxPortable]
FirefoxDirectory=App\firefox
ProfileDirectory=Data\profile
SettingsDirectory=Data\settings
PluginsDirectory=Data\plugins
FirefoxExecutable=firefox.exe
AdditionalParameters=-no-remote
LocalHomepage=
DisableSplashScreen=false
AllowMultipleInstances=true
DisableIntelligentStart=false
SkipCompregFix=false
RunLocally=false
=============== end =================

When I run the 2nd instance of FirefoxPortable (version 3.6.6 on WIndows XP), I get a new error message:

Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system.

Simeon
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2 separate copies

I think you have to run 2 separate copies and not 2 instances of the same copy.

"What about Love?" - "Overrated. Biochemically no different than eating large quantities of chocolate." - Al Pacino in The Devils Advocate

ppps
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Works with 2 instances and changes in FirefoxPortable.ini

Absolutely, it works with 2 instances and the changes made to FirefoxPortable.ini. Thanks for the tip.

CheckDisShiet
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Mah dude

Thanks you, this did the trick !

It even works with the "normal" version of Firefox !

I wish the other answer were as useful as yours though.

Cheers.

John T. Haller
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Firefox Portable 3.5.10 Launcher

I added the new commandline switch into the 3.5.10 FFP launcher (FirefoxPortable.exe). You can use the launcher with 3.6.6 as well. Please let me know if it works as expected for you.

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MiK
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Modified FirefoxPortable.ini and Mozilla Folder

Don't know if it matters but while playing with multiple instances, I noticed that running FF-Portable with a modified FirefoxPortable.ini causes the infamous "Mozilla" folder, created in the "Application Data" folder (winxp), to be left behind. Even when only one instance was launched.
Though, it's not left behind if it is created by running FF-Portable without the .ini or unmodified one, first, i.e. before launching other instances.

John T. Haller
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way it works

That's by design since the launcher can't tell which instance is going on. AllowMultipleInstances is only intended for your own pc.

Sometimes, the impossible can become possible, if you're awesome!

o.o
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AllowMultipleInstances no longer working?

Since around 3.6.15 or so (this latest batch of updates that came with ff4) it seems like AllowMultipleInstances is no longer working. I'm not exactly sure when it started, I only noticed it around this time period. I have AllowMultipleInstances set to true but it says another instance has been found. I'm wondering if anyone knows about this and why. And possibly a fix for it? thanks

edit: nvm, i found out in another thread https://portableapps.com/node/27019 that true and false somehow got flipped :S is it possible to correct this?

renu765
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You can get a lot of help

You can get a lot of help from this website:
http://www.techyv.com/questions/one-instance-already-running-error
It provided me on how to overcome the issue of "one instance already running" error.

Elstermann
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WORKS!

This solution was given by other authors as well - but i want to repeat and emphasis that it REALLY WORKS - and its simple as 1-2-3:

  1. From the directory where your "FirefoxPortable.exe" is (let's call it appRootDir) you go to directoty "Other\Source\"
  2. copy the file "FirefoxPortable.ini" to the appRootDir
  3. change line "AllowMultipleInstances=false" to "AllowMultipleInstances=true" in the copied "FirefoxPortable.ini" in appRootDir

I use this to run FFportable & FFportable developer edition at the same time...

John T. Haller
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Documented

This is documented right in the app's help/readme files, so it is not a secret.

The usual caveats apply. This will leave files behind on every PC. This will break Firefox's ability to open links from other applications. Firefox itself isn't really designed to be operated in this mode.

Sometimes, the impossible can become possible, if you're awesome!

ruskal
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regular and portable firefox simultaniously

This described solution works only with portable versions. Currently there is no way you can run the regularly installed ff and the portable instances simultaneously.
There is a workaround however that might be useful in some cases. The crucial point is: you must start one instance of FF in a sandbox (i.e. sandboxie, portable version of it is available to my knowledge, too) first and launch the other instance regularly after that.

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