Some Time when trying to control you VM from Hyper-V manager you might get request to change windows size and the you might get : “Video remoting was disconnected unexpectedly”
Although the VM is running and all seems to be in order .
The reason might be enhanced session mode being enabled on the hyper-v setting
To get access to the VM just go to Hyper-V Manager ->Hyper-V settings -> UN-mark the “allow enhanced session mode” settings and you will get control back .