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John99 posted that he is running several versions of Firefox. can someone walk me through how to do this before I try it on my own? I have a program that works better on version 3.6.18

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I have updated to v5, but the program that I am using crashes with v5 (PracticeFusion) They recommend using 3.6.18

I have updated to v5, but the program that I am using crashes with v5 (PracticeFusion) They recommend using 3.6.18

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You can install multiple versions but there are a few steps to take.

When you install the other version(s) of Firefox use the custom installation option and choose a different location to install Firefox.

In order to use multiple versions, you need to create a new profile for each version (Firefox stores user data in the profile). Using the same profile with different versions can cause problems. Once you create a new profile you can copy certain data such as bookmarks and passwords between them. You can also use Firefox Sync to keep the profile synchronized. Finally, you will need to set up shortcuts to launch the correct profile for each version.

The following links show how to do this:


An alternative approach is to keep Firefox 5 and install the portable version of Firefox 3.6 on your hard drive. The portable version will be totally independent of the main version and can be used when you want to access that site. You can get it from http://portableapps.com/apps/internet/firefox_portable

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IMO, your best option is Firefox Portable, available here:
http://portableapps.com/apps/internet/firefox_portable/localization#legacy36