Hi,

I am sure you will find the two drive capacities have to be identical, the manufacturer can be different but not the capacity, so I am afraid it is the following steps:

1: Full backup

2: Remove existing disks, do not format just incase you have issues with the next steps!

3: Fit new drives and wait for the TwinStore to format them.

4: Restore your backup.

5: Verify the library works?

Good Luck

Russ

PS: I just restored a large library onto a QNAP NAS, it worked perfectly.