I suggest you do a custom install of Firefox 19. Do not use it for anything other than the work required, because it is not supported or secure and is generally unsafe to use. I see no reason why any Government or large institute would want to use such a Firefox version. Presumably it is only used on private internal networks.

You appear to have posted from Window 10.

• Please see Install an older version of Firefox
  • assuming en-US version download https://ftp.mozilla.org/pub/firefox/releases/19.0.2/win32/en-US/
• edit: also see How to install Firefox on Windows but remember to use the Fx19 installer.

Remember to set that to not update as explained in the article. It is probably a good idea to keep hold of the downloaded installer. If you wish to confirm the version check by keying in to the address bar about:support do NOT try checking from the menu or orange button or it will try to force an update.

Note that you will almost certainly break Firefox if you try to run Fx45 and Fx19 sharing the same Firefox profile. (Firefox will try to do that !
Firefox does not expect you to try to run two versions.)

Instead of allowing a default install choose a location for the install folder for instance firefox19 the installer will create the folder.

When you first try to run Firefox after installing do so by creating a desktop shortcut to the firefox.exe and adding -P so that it starts with the profile manager. From there create a new profile. Use the location suggested. Give it a short meaningful name. I suggest work19. See

• Profile Manager - Create, remove or switch Firefox profiles
• https://developer.mozilla.org/Firefox/Multiple_profiles
  • This may be easier to read http://kb.mozillazine.org/Testing_pre-release_versions#Installing_multiple_versions

I forgot to add the actual installation guidelines

• * How to install Firefox on Windows but remember to download & use the Fx19 installer not the standard link.

John99 said

I suggest you do a custom install of Firefox 19.

i do every day i use the internet. i'm trying v. 20 now, but the download feature doesn't do it for me.

Do not use it for anything other than the work required, because it is not supported or secure and is generally unsafe to use.

really? because i've had absolutely no trouble with it, even with removing all the Googley spyware settings for safe browsing, etc.

I see no reason why any Government or large institute would want to use such a Firefox version.

well, i'm a private individual, but perhaps it's because after 19, Firefox started being designed really, really poorly.

Presumably it is only used on private internal networks.

nope; world wide web, baby!

PS: quick DL link to v. 19 at Mozilla -- link deleted by a moderator

locking this solved thread - this forum doesn't allow obfuscated links to executable files for direct downloads