The easiest way with out any mucking about is to have the Firefox you have installed. Make backups of these as you should all the time :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Install Firefox Developer Edition as it has a compatibility mode in it.

• https://www.mozilla.org/en-US/firefox/developer/

Note the above is always in beta and there can be issues, it shares your bookmarks, and updates daily, almost. You do not need to use the tools unless you want to.

For that issue of consuming all your ram please see :

• https://support.mozilla.org/en-US/kb/performance-settings

Go the 3 Bar Menu then Options --> General --> Performance and untick everything. change the recommended size lower then see how it runs. Note: 1 = No Multiprocessor = slow again. Try 2 Restart Firefox after making these changes please.

Note : Acceleration is for your Video Card, monitor to see if need to turn back on.

Please update your Flash from ver 28 Flash Player Version: 29.0.0.113 Current Version https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, . . . .) Note: Other software is offered in the download. <Windows Only>

Please let us know if this solved your issue or if need further assistance

I sometimes run two different versions of Firefox. Each must be started with special options on the command line. For example (all on one line);

C:\PROGRA~1\MOZILL~1\firefox.exe -no-remote -new-instance -new-window -P Firefox_v_57

https://developer.mozilla.org/en-US/docs/Mozilla/Command_Line_Options

Usage: C:\PROGRA~1\MOZILL~1\firefox.exe [ options ... ] [URL]
      where options include:

 -h or -help        Print this message.
 -v or -version     Print Firefox version.
 -P <profile>       Start with <profile>.
 -migration         Start with migration wizard.
 -ProfileManager    Start with ProfileManager.
 -no-remote         Do not accept or send remote commands; implies -new-instance.
 -new-instance      Open new instance, not a new window in running instance.
 -UILocale <locale> Start with <locale> resources as UI Locale.
 -safe-mode         Disables extensions and themes for this session.
 -console           Start Firefox with a debugging console.
 -jsconsole         Open the Error console.
 -browser           Open a browser window.
 -new-window  <url> Open <url> in a new window.
 -new-tab     <url> Open <url> in a new tab.
 -preferences       Open Options dialog.
 -search     <term> Search <term> with your default search engine.
 -setDefaultBrowser Set this app as the default browser.

I think I may not have been clear in describing the issue. The portable version is set as the default browser.

With neither browser open... When I click on a link in an Outlook email or double-click a shortcut on my desktop, Firefox Portable should open the webpage. That does not happen. What does happen is a process (firefox.exe) is started and in the Task Manager, I see it consumes all system RAM. A Firefox window never opens and I have to kill the process. Again, this happens only when clicking on links in documents or shortcuts.

Other than this issue, the two browsers seem to function properly even when both are running simultaneously.

I need two browsers because I use different settings for each and I have different extensions installed in each version. I don't need a portable version if installing two versions would work better.

Thanks!

jeffshead said

I need to run two instances of Firefox simultaneously. I currently have FF54 x32 installed and have the portable version of FF59x64.

Why? Is there some kinda security or tracking problem here?

jeffshead said

I have the portable version set as my default browser. I can have both running at the same time. The problem I encounter is when I click on a link in an email or a website shortcut on the desktop, Firefox does not open but I do see a firefox.exe process in the Task Manager that consumes all 16GB of RAM. I have to manually stop that process. The exe for the portable version is actually named FirefoxPortable.exe.

This is what I expect to happen when you install two of the same Browser regardless of bit version.

jeffshead said

So how can I have two versions of Firefox (or two instances of the same version) and still be able to have Firefox open links and shortcuts?

Realistically it won't happen like you think it should when running two of the same Browser at the same time. If the Addon/Extensions isn't working in FF59 then you need to contact the Addon creator to update to work with FF59. End user forum doesn't provide help with outdated FF versions unless that is FF54 is the latest ESR version.

jeffshead said

I think I may not have been clear in describing the issue. The portable version is set as the default browser.

The way it sounds like both Browser thinks they are the default and conflicting when you try to open Docs/Links as your seeing happen.

jeffshead said

Other than this issue, the two browsers seem to function properly even when both are running simultaneously. I need two browsers because I use different settings for each and I have different extensions installed in each version. I don't need a portable version if installing two versions would work better.

Your causing yourself more problems then fixing them. Having two of the same Browser family installed is asking for problems like what your having program conflicts. Either choose FF54 if outdated but get no support on outdated Browser or use updated FF59 and get proper support and tell Addon/Extensions creator to update their program to work with FF59. That is what will keep a stable Browser environment. Not doing this and then expecting End User forum help is being disingenuous here.

WestEnd said

...then expecting End User forum help is being disingenuous here.

Definition of disingenuous: Not candid or sincere, typically by pretending that one knows less about something than one really does.

Geez... I truly hope you mistakenly chose the wrong word and that you did not mean to attack my character because that's what you did.

I came here seeking help because I need two browsers with different settings and extensions. For years I was using IE and Firefox. For the past few years I've been using Chromium browsers and Firefox together without issue. Two to three months ago, I started getting random computer freezes. No BSOD, no dump file and no entries in the event viewer. I have tested everything including trying every available driver, swapping video, sound, network cards, using onboard video/sound/NIC, different PC's with different chipsets, mem86 tests, new RAM, upgrade/in-place repair OS installs, fresh vanilla installs, etc. I have been freeze free since I stopped using the Chromium browser several days ago.

I've searched and I've read posts and articles that say it can be done but it appears that it cannot be done. That's why I came here for help. I wanted to know if two Firefox instances can work together so I can stay clear of Chrome and Chromium based browsers.

Pkshadow said

The easiest way with out any mucking about is to have the Firefox you have installed. Make backups of these as you should all the time :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Install Firefox Developer Edition as it has a compatibility mode in it.

• https://www.mozilla.org/en-US/firefox/developer/

Doesn't work. I have checked the "Allow Firefox Developer Edition and Firefox to run at the same time" box but when I try to open FF54x32, FFDE opens instead. I also tried creating a shortcut, for FF54 and added "-p "default" -no-remote" parameter but I encounter the same issue with firefox not opening but spawning a process that eats all RAM, instead.

jeffshead said

WestEnd said

...then expecting End User forum help is being disingenuous here.

Definition of disingenuous: Not candid or sincere, typically by pretending that one knows less about something than one really does.

Geez... I truly hope you mistakenly chose the wrong word and that you did not mean to attack my character because that's what you did.

I came here seeking help because I need two browsers with different settings and extensions. For years I was using IE and Firefox. For the past few years I've been using Chromium browsers and Firefox together without issue. Two to three months ago, I started getting random computer freezes. No BSOD, no dump file and no entries in the event viewer. I have tested everything including trying every available driver, swapping video, sound, network cards, using onboard video/sound/NIC, different PC's with different chipsets, mem86 tests, new RAM, upgrade/in-place repair OS installs, fresh vanilla installs, etc. I have been freeze free since I stopped using the Chromium browser several days ago.

I've searched and I've read posts and articles that say it can be done but it appears that it cannot be done. That's why I came here for help. I wanted to know if two Firefox instances can work together so I can stay clear of Chrome and Chromium based browsers.

Hi, you can report westend to the right if wish to .

For chewing up all your resources can do this : You could try this please : Go the 3 Bar Menu then Options --> General --> Performance and untick everything. change the recommended size lower then see how it runs. Note: 1 = No Multiprocessor = slow again. Try 2 Restart Firefox after making these changes please.

Note : Acceleration is for your Video Card, monitor to see if need to turn back on. https://support.mozilla.org/en-US/kb/performance-settings

Only thing can suggest is wipe out all Firefox and start over, including the registry. As for Developer Edition it probably is not compatible with 54 as it is not Quantum but..... As for the Portable, I never find it works as intended. Better off installing a full version. https://www.mozilla.org/firefox/all/

Best to follow Fred's idea but is a hassle.

Please let us know if this solved your issue or if need further assistance

If you start both Firefox instances with the -no-remote command line then you won't be able to open external links in t=either these instances because -no-remote hides that Firefox instance from the OS.

You will have to start at least one instance with this switch to be able to open external links.

Found the issue. I have been using Jumplist Launcher for years. For some reason, since installing FF Developer edition, FF54 x32 will no longer open when clicking the link in the Jumplist. It opens FF Developer Edition instead even though the link points to the correct executable. I created a batch file that opens FF54 x32 and added that to Jumplist Launcher and that works!

So now I have FF54 x32, FF portable and FF Developer Edition running simultaneously without any issues. FF Developer is my default so it opens when I click on any links or shortcuts.

My goal is to get rid of the portable version and replace FF54 x32 with the latest FF x64 so I have the latest stable and Developer versions, only.

Thanks to everyone for taking the time to share your expertise. I really appreciate it :-)