This is a short Howto on sharing profiles for Firefox & Thunderbird between Win & Linux
(other shared situations see below). You need to exactlcy follow these steps, otherwise certain functions would not work correctly:
1) First have your profiles set up correctly under Win. Then from inside these programs move the profiles destination to a FAT32 partition (i.e. your data partition D:\profiles\firefox & D:\profiles\thunderbird). Correct the paths in both settings, don't forget to fix paths also for signatures, etc. Then restart the programs and check if all went fine.
2) Go to Linux and set up standard profiles in Firexfox & Thunderbird. Don't care for correct settings - you may delete these dummy profiles later, so no matter what you fill in there.
3) Edit /home/username/.mozilla/firefox/profiles.ini:
4) Correct your /home/username/.mozilla-thunderbird/profiles.ini:
5) Start the programs and test. First time takes some time, but you should now fully share bookmarks, cookies, settings, accounts, messenges, adressbooks and passwords between both OSes. Different plug-ins and even program versions do not harm any more.
The same procedure may be used to share multiple profiles; or to share the same profile between networked machines (however, only one user can open the same profile at the same time). If necessary, you may even be able to put your profiles in an encrypted file system at an USB-stick or a web server, using the same method.