Firefox 4 can co-exist quite happily with previous versions, but unfortunately the way Mozilla has done this has created problems, specifically by default both versions will use the same profile folder (location where Firefox stores user data). Switching between different versions of Firefox using the same profile folder can cause problems.
The beta by default installs in a different location than the release version, for example on 32 but Windows the default installation directories are:
Release version: C:\Program Files\Mozilla Firefox\
Firefox 4 beta 9: C:\Program Files\Mozilla Firefox 4.0 Beta 9\
If you want to use both versions, you should set up a new profile folder for Firefox 4 beta, and create shortcuts to launch the correct profiles for each version. The Mozilla support article concerning creating profiles can be found here -
https://support.mozilla.com/en-US/kb/Managing+profiles" onclick="window.open(this.href);return false;
There is some good information about managing profile on the Mozillazine knowledge base. There are currently intermittent problems with Mozillazine, so if the following links do not work try again later.
http://kb.mozillazine.org/Creating_a_ne ... on_Windows" onclick="window.open(this.href);return false;
http://kb.mozillazine.org/Shortcut_to_a ... ic_profile" onclick="window.open(this.href);return false;
http://kb.mozillazine.org/Testing_pre-release_versions" onclick="window.open(this.href);return false;
You can copy data such as bookmarks and passwords to the new profile, for details see
http://kb.mozillazine.org/Transferring_ ... _-_Firefox" onclick="window.open(this.href);return false;
You will only be able to have one version of Firefox open at a time, if you want to have both versions open at the same time you need to add the -no-remote command line argument to the shortcut.
