Sunday, January 13, 2008

VMs Disappearing from Microsoft Virtual Server

I know this isn't specifically a SharePoint issue, but...

I use Microsoft Virtual Server to run all the SharePoint VMs that I use. At any given time, I may have 4-6 VMs on my notebook computer. Recently I ran into a problem where I kept losing my VMs that I set up on Virtual Server. Each time I came back into the Virtual Server administration web site (after restarting my notebook) my VMs that I set up from the last time would be missing. This caused me to have to go into the directory C:\Documents and Settings\All Users\Application Data\Microsoft\Virtual Server\Virtual Machines and delete all the VM shortcuts so I could re-add the VMs. Sometimes I had to create the VM again. However, all the Virtual Network shortcuts seemed to be unaffected. In all cases, the VHD and VMC files were was just the shortcuts that were causing the problem. I had been living with this problem for the last several months.

The Solution:
I felt like there was a problem somewhere in the permissions, so I finally started poking around. Sure enough, I found that there were some permissions that were not being correctly inherited from C:\Documents and Settings\All Users\Application Data\Microsoft\Virtual Server. I'm a little rusty on setting advanced permissions, so it took me a while to figure out how to make the correct permissions inherit to the Virtual Server sub-directories, but I finally figured it out. The Network Service didn’t have the appropriate permissions to the Virtual Machines directory. I finally found
this MSDN documentation that details the DACLs for the Virtual Server directory. The NETWORK SERVICE entries in the following table were the permissions that were missing and not correctly being inherited by the sub-folders.

NETWORK SERVICERead & executeThis folder, subfolders, and files
NETWORK SERVICECreate Files/Write Data Create Folders/Append DataThis folder only

Whew! Finally got that fixed!

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