Maybe use the Portable build, which runs out of a decompressed folder instead of having to install?

This page will always have the latest version: http://portableapps.com/apps/internet/firefox_portable/

Older versions are available in Sourceforce: http://sourceforge.net/projects/portableapps/files/Mozilla%20Firefox%2C%20Portable%20Ed./

Also, versions 24 and 31 (except 31 ESR) are not secure. Mozilla discloses security flaws after each new release.

Portable Apps sounded a good solution, but it is not actually working. Although the portable installation works fine, whenever I try to start it I either get an error telling me that another instance is running, or it simply opens the window of the installation that is already running. Any thoughts?

As for security ... are any of them really secure <g>. In fact it is the ESR version I want to do this with, so I can evaluate the latest update and decide whether I want to make the transition at this point.

-Danny.

Hi Danny, somehow I forgot to mention that even though the Portable build runs out of its own folder, Firefox will normally not allow two instances of itself to run simultaneously. So it's certainly not ideal for a side-by-side comparison.

A possible workaround might be to start the Portable version first, and then start your normal installation with the -no-remote startup switch; I haven't tested it. This article has more info on startup switches:

• https://developer.mozilla.org/docs/Mozilla/Command_Line_Options

Also, see:

http://kb.mozillazine.org/Opening_a_new_instance_of_Firefox_with_another_profile

I suppose it does not have to run simultaneously. If I can just have the separate installation running from the portable device, that would be sufficient for my comparison.

However, the portable-app seemed to somehow reset the settings on my main profile on the computer. When I went back to the main set up almost all the settings had been changed back, my add-ons were gone and even some of the backup files had been deleted. Frankly, I have been beating my head against the wall and can not understand why that happened although, fortunately, I did have some backups in another directory that I was able to use to restore almost everything and I had my collection of add-ons available to reinstall.

From here I intend to try two things, after reading the article, you suggested: First, I will make a complete backup of my main system with the FEBE program, and I will try to import that backup into the setup on the on the portable drive. If I can do that without harming the set up on my PC and I can run each program independently, without affecting the other, then at least I can have both configurations running and can do a complete comparison. At that point I can try again to get them to run simultaneously and see what happens.

I will update you on this experiment <g> when it is complete.

Thanks again,

-Danny.

The portable build is supposed to use a profile in its own folder hierarchy, and not touch anything belonging to the installed Firefox. However, I don't use it very often so there could be glitch I'm not aware of.

Is there a new Old Firefox Data folder on your desktop? If so, your main install of Firefox might have performed a reset. The contents of this folder could be a little fresher than your backup.

RE: "Old Firefox Data folder on your desktop"

No, nothing like that. In fact, I cannot find any defined profiles on the portable apps installation. I need to try it again, but still not before I more fully protect the PC based installation.

-Danny.