Can't import a VM

Hello!

There's a test PC (Server 2012R2)  with two network cards (Nic1=Realtek, Nic2 = Dlink). Some days ago I created a VM on this PC and created a couple of checkpoints for the VM. Today I formatted the PC's disk C, tried importing this VM and failed:

If i choose the Realtek virtual adapter from the list the error persists:

So I don't understand

1) Why Hyper-V "can't find" the switch that's available for selection

2) Is a vm (or a snapshot of the vm) bound to a specific virtual adapter and can't be used with any other one? (If so I would be suprised...I re-attached replica VMs to other virtual switches many times without any problems...

Thank you in advance,

Michael