Suppose that you have installed two or more OS in a box, such as Windows and GNU/Linux, and you are going to share data/configuration between them, e.g. firefox and thunderbird. How to do that?
For Windows 7, edit C:Users<your user name>AppDataRoamingMozillaFirefoxprofiles.ini or C:Users<your user name>AppDataRoamingThunderbirdprofiles.ini . Update configurations:
For Linux, edit /home/<your user name>/.mozilla/firefox/profiles.ini or /home/<your user name>/.thunderbird/profiles.ini