Hyper-V Beta released as part Windows Server 2008. The final release of Hyper-V happened shortly after the Windows Server 2008 release and can be downloaded here. After a few months of supporting customers, we now have enough case data to report on the top issues being reported for Hyper-V. The issues are categorized below with the top issue(s) in each category listed with possible resolutions and additional comments as needed. These may change as time passes, but as of this post, this is how we see it here in CORE. As always, we welcome your comments.
Customers looking for Hyper-V documentation.
Resolution: Information is provided on the Microsoft Hyper-V TechNet Library which includes links to several Product Team blogs. Additionally, the Microsoft Virtualization site contains information that can be used to get a Hyper-V based solution up and running quickly.
How to migrate virtual machines from Virtual Server 2005 to Hyper-V?
Resolution: The CORE Team blog provides tips and suggestions to help with the migration process.
System hangs on restart at “Configuring Updates Stage 3 of 3” after the Hyper-V role is enabled, disabled, or updated.
Cause: HP Network Configuration Utility.
Resolution: Perform the steps documented in KB950792.
After the Hyper-V role is installed, a virtual machine fails to start with the following error:
The virtual machine could not be started because the hypervisor is not running
Cause: Hardware virtualization or Data Execution Prevention (DEP) was not enabled in the BIOS.
Resolution: Enable Hardware virtualization or DEP in the BIOS. In some cases, the server must be physically shutdown in order for the BIOS settings to take effect.
A Synthetic NIC was listed as an unknown device in device manager.
Cause: Integration Components were not installed.
Resolution: Install Integration Components package in the VM.
Unable to associate the virtual COM port to a physical COM port.
Cause: By design.
Dynamic disks attached to the SCSI controller in a Windows Server 2003 virtual machine show as Offline on restart.
Cause: Storsvc is set to the incorrect start value in the registry.
Resolution: Perform the following step in the Guest OS registry:
Change the “Start” value from 3 to 0.
Additional Comment: This has been fixed in Windows Server 2008 SP2.
Attempting to install the Integration Components in a Windows Server 2003 virtual machine fails with the following error:
Unsupported Guest OS
An error has occurred: The specified program requires a newer version of Windows
Cause: Service Pack 2 for Windows Server 2003 wasn’t installed in the virtual machine. You can hit this error for other OS’ that don’t have the appropriate service pack installed (Vista, Windows XP, etc..).
Resolution: Install SP2 in the Windows Server 2003 VM before installing the integration components.
Virtual Machine State and Settings
Virtual machines show a state of “Paused-Critical” in the Hyper-V Management Console
Cause: Lack of free disk space on the volume hosting the .vhd or .avhd files.
Resolution: Free up disk space on the volume hosting the .vhd or .avhd files.
When you attempt to create or start a virtual machine, you receive the following error:
The requested operation cannot be performed on a file with a user-mapped section open. (0x800704C8)
Cause: This issue can be caused by antivirus software that is installed in the parent partition and the real-time scanning component is configured to monitor files used by Hyper-V.
Resolution: Configure the real-time scanning component within the antivirus software to exclude the following files and directories:
- Default virtual machine configuration directory (C:ProgramDataMicrosoftWindowsHyper-V)
- Custom virtual machine configuration directories
- Default virtual hard disk directory (C:UsersPublicDocumentsHyper-VVirtual Hard Disks)
- Custom virtual hard disk directories
- Snapshot directories
Additional Comment: A KB article is forthcoming.
High Availability (Failover Clustering)
Virtual machine settings that are changed on one node in a Failover Cluster are not present when the VM is moved to another node.
Cause: The ‘Refresh virtual machine configuration’ option in the Failover Cluster Management interface was not used prior to moving the VM to another node in the cluster.
Resolution: When virtual machine settings are changed in a VM that’s running in a Failover Cluster, you must select the ‘Refresh virtual machine configuration’ option before the VM is moved to another node.
Additional Comment: We have a CORE blog which discusses this issue.
Customers looking for documentation on how to configure Hyper-V in a Failover Cluster.
Resolution: A step-by-step guide is available which covers how to configure Hyper-V in a Failover Cluster.
Snapshots associated with a VM are lost.
Cause: Parent VHD was expanded.
Resolution: Restore data from backup.
Additional Comments: There is a warning about this in the Edit Disk wizard which should not be ignored.
Virtual machine fails to boot.
Cause: Virtual machine had associated snapshots and to recover disk space the .avhd files were deleted.
Resolution: Restore data from backup.
Backup (Hyper-V VSS Writer)
How to backup virtual machines using Windows Server Backup (WSB).
Hyper-V Management Console
When remotely managing a Hyper-V Server and trying to perform a task such as creating a virtual machine or modifying virtual machine settings, you may receive the following error:
You might not have permission to perform this task
Cause: There are multiple causes for this error but the most common cause is that a beta version of the Hyper-V Management Console was being used to manage a Hyper-V server that was running the RTM build.
Resolution: Install the RTM version of the Hyper-V Management Console.
Additional Comment: There is a multi-part Product Group blog that discusses this error and provides several possible solutions which are scenario dependent.
Senior Escalation Engineer
Microsoft Enterprise Platforms Support