While trying to adjust the memory of a VM from 512MB to 256MB, my VM entered an endless BSOD reboot cycle.

Background:

• Upgraded install of VMServer 2.0.1
• Brand new Windows Server 2008 64bit Guest OS (Server Core)
• Started out with 512MB of ram for the guest. Installed OS, renamed computer, joined domain
• Shut down the VM and adjusted the memory

Tried all safe mode options, and would always get a Stop code of 0xD1 for ACPI.Sys, DRIVER_IRQL_NOT_LESS_OR_EQUAL. Remember to press F8 to get to the windows boot options menu which allows you to disable automatic restart, which will let you examine the stop screen in detail.

I did quite a bit of searching but could not come up with anything for how to resolved this. I even stopped searching for VMWare Server specific stuff and just searched on the stop code. Finally I shut the VM down and changed the memory back to 256, and it finally worked.

So I went from 512MB to 256MB, failed, back to 512MB, failed, and then back to 256MB and it worked. The only thing I can think of was that the memory reconfiguration was not successful behind the scenes in VMWare.

I’m not all that comfortable moving forward without a definitive solution, but it will have to do for now.