if i convert a MBR drive to GPT, will the data on it be preserved?

I'm trying to do a "Fred Flintstone" upgrade to Win 7 Ultimate from 7 Home premium on my PCIe drives - but what i'm going to do is upgrade a backup Sata drive (that's i've got a clone of the PCIe's 7 Home Premium on.

Problem is, the win 7 ultimate upgrade won't install on the drive because it's set to GPT partition

just trying to saving myself loosing some time

tks
 
got to love windows - the windows 7 ultimate upgrade had installed the other day fine, the after downloading a ton of windows updates, had one or two left and it crashed the system giving me a redbox error message on boot that "firmware or hardware has been changed..."

okay, got the system up and running on a backup clone disk that had a copy of the original win 7 home premium that i had upgraded on the samsung NVMe PCIe SSD - tried to re-install the upgrade and get the error message the "disk is partitioned GPT and must be MBR partitioned for installation". Okay, so i partition it to MBR and on the next attempt to installi get the message, "cannot install to this disk, it is partitioned MBR and must be GPT for a UEFI platform".

Why do i get the sense MS is doing all it can to push me to windows 10