Dual booting Windows and Ubuntu and still need to share the same settings and data from Firefox and Thunderbird between your two favorite OSes? It's much easier than you think.

First you'll need a place to store the data which is visible in both OSes. If you have a separate FAT32 partition -- a strategy used by many a dual-boot wizard -- that's a great start! Create a directory on that partition called 'share' and inside that, create one folder for Firefox and one for Thunderbird.

Next, copy your current Firefox and Thunderbird data to the new directory. You can't merge your existing profiles from Windows and Linux so, you'll have to choose your favorite. Under Linux, the Firefox data you need will be stored in ~/.mozilla/firefox/ and the data for Thunderbird should be in ~/.mozilla-thunderbird/Profiles. Copy the data from those directories the new directory we created in the first step.

(If you're looking for your Thunderbird and Firefox data under Windows, you'll likely find it in C:/Documents and Settings/user/Application Data/Thunderbird/Profiles/ )

Finally, you'll need to create a new profile under both the Windows and Linux versions of each program. The easiest way to open the profile manager in both applications is from the command line. In Windows you'll open the command prompt and run 'thunderbird.exe -profilemanager' and 'firefox.exe -profilemanager'. In Linux the applications have different filenames('mozilla-thunderbird -profilemanager' and 'firefox -profilemanager', but you'll notice it's still the same command line switch.

Use profile manager to create a new profile (and delete the old.. make sure you have a backup!) and set the profile directory to the newly created copy under that 'share' folder we created in step one. Presto! Now you're using the same data in Linux and Windows for your favorite browser and Email client.

Thanks Shevin!