Newer version of firefox use a different file format for storing bookmarks and other data, which means it is no longer possible to transfer information between the two. If you want, you can use two separate folders to store your firefox data for each version. Firefox Portable will let you do this, but note that it is not made by Mozilla.

Portable Apps is Windows OS only programs - they don't have a Mac version of Firefox Portable. I have seen a few different versions (in past years) of 'Portable' that were made by a Mac Users Group, but nothing as "new" as 3.6.28.

What the thread owner needs is a separate Profile for each version of Firefox, and a specific desktop shortcut so that the correct Profile is launched. I don't know how that is done on a Mac. Here's the KB article about Profiles. Profiles - Where Firefox stores your bookmarks, passwords and other user data

See this article about how to install multiple versions on Mac OS X:

• http://www.businessinsider.com/how-to-run-firefox-4-and-3-simultaneously-in-mac-os-x-with-multiple-firefox-profiles-2011-3

Yes it sounds like you are sharing the same Profile between the major difference of versions.

The basics has always been to have Firefox versions in separate folders and have each version with its own Profile.

If you use the Time Machine then you could try to restore the file(s) from that backup.

• http://www.apple.com/support/timemachine/

• https://support.mozilla.org/kb/Recovering+important+data+from+an+old+profile
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Thanks a lot, I created a second profile instead of sharing the profile for both version and it works perfectly!