how do I transfer hard drive from old to new Xbox one?

The best thing I can tell you to do is transfer any games that are currently stored on your Xbox One to the new hard drive. After doing that hook the old one up to your Xbox and transfer the games from that hard drive to your Xbox. Put the 2 TB drive
back in and transfer to it from the system. Wash rinse repeat.

you can do this with the xbox transfer cable
www.xbox.com/.../Xbox-360-Hard-Drive-Transfer-Cable, connect it to the old xbox hard drive then connect to your xbox slim using one of the usb ports, here is a guide that may help you.

www.gamefront.com/how-to-transfer-old-xbox-360-data-to-a-new-xbox-360-slim

you can take the hard drive from one console to another no problem.

There is only restriction to this... the only way you can use the hard drive from the old style XBOX 360 on the new "SLIM" 360 is the following:

Using a USB transfer kit, you can plug the old style xbox hard drive into the new SLIM XBOX. You can then transfer stuff to the new XBOX. Note that in this setup, you can't use the old style hard drive for anything other than transferring stuff over.

If both XBOX 360 are the old style, there is no problem, just pop the hard drive off one 360 and plug it into the other one.

Note that disassembling the hard drive unit (to take the bare drive out) is not supported, and is a terms of use violation.

you can do 2 things one buy a xbox hard drive transfer cable( newest one) and transfer everything in one go(it will erase everything on the old hard drive be careful to read the instructions) or 2 you can use a flash drive up to 32 gbs formatted on the
xbox any brand would do. and manually transfer everything on the old hard drive to the flash drive to your new hard drive it is a bit time consuming and i would recommend after to do the upgrade to the new system regardless of you methods of transferring your
data. to do a license transfer after all that is complete to play any games you downloaded .

I don't know if this will help anyone, it may it may not.

i found that by transferring from old (20gb) xbox to the new hard drive works, just take the hard drive out of your new xbox plug in transfer cables and choose the option to transfer FROM xbox, did the trick for me, might do the trick for you.