When running a Windows XP or 2003 in VirtualBox, under certain circumstances, the guest may generate a BSOD when booting. The message of the BSOD is a:

DRIVER_UNLOADED_WITHOUT_CANCELLING_PENDING_OPERATIONS

It is accompagnied by a referral to processr.sys, intelppm.sys or p3.sys, depending on the CPU used to install the machine.

The cause

The reason for this BSOD is a problem with these drivers, trying to perform an unsupported operation inside the virtual machine (like updating microcode or changing the power state of the CPU).
The issue usually surfaces when the guest machine is moved to a different system with different CPU time.

The solution

To resolve the issue, the processor drivers have to be disabled. This can safely be done as they are not needed in a virtual machine.

1. Start the Registry Editor, and navigate to the key
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Processor
2. Set the value of Start to 4
3. Navigate to the key
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Intelppm
4. Again, set the value of Start to 4

Additional information

Since 2003 R2, this issue has been resolved, because the drivers have been made more intelligent.

Sources:

• http://forums.virtualbox.org/viewtopic.php?t=1560
• http://blogs.msdn.com/virtual_pc_guy/archive/2005/10/24/484461.aspx