I don't know if this is going to be any real help, but out of curiosity sake I just plugged up a 2TB external and another 1TB that I have laying around and it didn't seem to have any issues with reading data off either.. Obviously I didn't sit there and try every single file, but all data was showing.. Both external drives are Western Digital..
To give my opinion on your 2nd enquiry, a have never had an issue with gui format.. That's just my opinion though.. Hope I have been of some help..
EDIT: Forgot to say Hi, as this is my first post, so HI ALL!!