Q: I'm trying to import an exported virtual machine (VM) from Windows Server 2008 R2 into Windows Server 2012 R2, but it's not working--why?
A: If you try to import a VM that was exported with Windows Server 2008 R2 into Windows Server 2012 R2, the import process will say that Hyper-V didn't find virtual machines to import from the location you specified.
This is because Windows Server 2012 R2 import only supports importing from Windows Server 2012 and Windows Server 2012 R2. To import those VMs exported using Windows Server 2008 R2, you will first need to import to a Windows Server 2012 machine, then import those files into Windows Server 2012 R2 (either by exporting from Server 2012 or just directly importing the files from Server 2012). Export isn't actually required to import with Server 2012 and later.