When you try to perform Item Level Recovery (ILR) in System Center Data Protection Manager 2010, you may get the following pop-up message:
DPM cannot browse the contents of the virtual machine on the protected computer <name>. Item level recovery is not supported in the following scenarios.
1. The VHD contains a dynamic disk inside the guest OS.
2. The VHD has no volume.
3. HyperV role is not installed on DPM server.
Please perform a full restore of the virtual machine.
Details: Internal error code: 0x80990A9E
The error is pretty explicit as to the cause of the issue, but what if you're seeing this because the Hyper-V role isn't installed, and the reason it's not installed is because the DPM Server is installed in a Virtual Machine?
When DPM 2010 performs an item level recovery, it actually mounts the VHD from the backup as a mountable file system on the DPM server itself. Unfortunately, Windows Server 2008 (inside a guest) does not provide a way to mount a VHD if you are actually in a VM already, so a virtualized DPM server can’t mount the volume – hence the error.
Fortunately there is a workaround we can use, which is to restore the .VHD as a file then mount it manually using Windows Server 2008 R2 disk management. From there you can browse the contents of the .vhd file system and manually restore your files.