MR14-1 seems a build with some bugs in importing/upgrading backup from MR14 or other Hardware. I have similar problems, i can´t upgrade from MR14 to MR14-1 and i can´t restore MR13 or MR14 Backups into other SOFS Devices.
But even XG18 Build was not able to restore MR13 backups from a SG210r1. Last time i got this working was a SFOS with 10 NIC´s (Test migration from SG210r1).
And sophos seems to have no real interest in solving this (case already open for 3 weeks).
Even Sales germany is not responding to mails.
The guideline for backup-restore compatibility check is not helpfull as the information are incorrect and the debug logs show other sign of failure. But the guideline is wrong.
good luck.
Best way would be to migrate by paper (write down all rules, settings etc and reinstall the new machine).
