Some notes on USB to USB directly...
As you will have found, you can copy and transfer your Thunderbird Profile, but you can't just use a ordinary USB cable from USB port to port if that's what you thought of doing.
A USB cable has four contacts, two are for the signal and two carry a 5 volt current. Connecting two ports directly will give you a short circuit and likely do real damage. I've had the occasion to save some eager friends from some costly problems.
You need to use a storage medium for the transfer; that's what a USB thumb drive or an external HDD is for. There are also special transfer cables if you need to move and co-ordinate files directly between two systems. Some of them work under linux.
If for some reason your installed linux will not find and mount the right file, you can use a linux live-CD that should see all the files on any device that can be mounted.
Last edited by thorkelljarl; 09-08-2014 at 11:11 AM.