The VMBus device does not load on a virtual machine that is running on a Windows Server 2008-based computer that has Hyper-V installed

Consider the following scenario.

• You have a Windows Server 2008-based computer that has Hyper-V installed.
• You create a virtual machine on the Windows Server 2008-based computer.
• You create the virtual machine from a virtual hard disk image (.vhd file) that was created by using Microsoft Virtual Server 2005 or Microsoft Virtual PC 2007.

In this scenario, the VMBus Integration Services device does not load. When you open Device Manager on the virtual machine, a yellow triangle that has an exclamation point on it appears next to VMBus. When you double-click VMBus, the VMBus Properties dialog box displays one of the following messages:

This issue occurs because the hardware abstraction layer (HAL) is not automatically updated in Windows Server 2008. (This is also true in Windows Vista.)

When a virtual machine is created by using Virtual Server or Virtual PC, the Advanced Configuration and Power Interface (ACPI) HAL is used. The Integration Services require an Advanced Programmable Interrupt Controller (APIC) HAL to load the VMBus device correctly.

To resolve this issue, follow these steps:

1. Start the virtual machine.
2. Click Start, click Run, type Msconfig.exe, and then click OK.
3. In the System Configuration dialog box, click the Boot tab, and then click Advanced Options.
4. In the BOOT Advanced Options dialog box, click to select the Detect HAL check box, and then click OK.
5. Click Yes to restart the virtual machine.
6. After the virtual machine is restarted, open Device Manager, and then verify that all Integration Services devices are installed.
7. In Device Manager, expand Computer, and then verify that an APIC-based PC HAL is listed. For x86 virtual machines, this item will be listed as APIC x86-based PC. For x64 virtual machines, this item will be listed as APIC x64-based PC.

Note You can clear the Detect HAL check box that you selected in step 4. If the Detect HAL check box is selected, the virtual machine takes a slightly longer time to start.

For more information about Hyper-V technology, visit the following Microsoft Web site: