Because I said I would heres a print screen of the disk manager
for a fix what I'm doing is using my server to copy all the data from the 1st LUN to a 2ND lun (one perk of thin provisioning)
I made sure to select allocation unit size of 4096 and it didn't have any trouble making a 4TB partition (or well 3.5, I rounded it down from 3.6 because as you know a 2TB drive is not quite 2TB and the differance adds up