There are 2 possible solutions to resolve the export issue:
1) Review if Hyper-V role is necessary on the protected machine. If it's not a necessary role, then:
- open Server Manager on the protected machine, Roles and Features
- remove the Hyper-V role and reboot
- force a new snapshot and export that snapshot it to the Hyper-V host
2) Use Bare Metal Recovery (BMR) procedure to the Hyper-V VM
- create a new Hyper-V VM with adequately sized disk
- create BootCD ISO using Core Console, More (...), BootCD
- follow BMR procedure using this KB article https://support.quest.com/kb/184594/how-to-perform-a-bare-metal-restore-for-a-windows-machine