When you move a virtual machine from Virtual PC to Virtual Server (or from Virtual Server to Virtual PC) you will get a warning message stating that the virtual machine was made by a different program and 'may not work'.  A number of people have had questions about this - so I will attempt to answer them here.

1. What are the potential problems moving a Virtual PC virtual machine to Virtual Server?
   
   Virtual Server does not emulate a sound card.  That is about it.
   
   
2. What are the potential problems when moving a Virtual Server virtual machine to Virtual PC?
   
   There are two problems here.  First - Virtual PC does not emulate a SCSI controller; so any SCSI virtual hard disks will not appear when the virtual machine is booted.  Second - Virtual PC has a more limited set of IDE configurations that it can support than Virtual Server (only one CD, etc...).  If a Virtual Server virtual machine has an IDE configuration that is not supported under Virtual PC - we will attempt to move the hard disks and CD's around in order to make things work - however there may be cases where IDE devices will not appear (for example - if you configured two CDROMs - only one will appear under Virtual PC).
   
   
3. I have a virtual machine that I configured without a sound card, without SCSI, with only one CD-ROM and a safe IDE configuration.  Why do I keep on getting this error message?
   
   The short answer is - you know it is safe but we do not.  The error message you are seeing is a general 'version checking' logic.  Because we have no idea as to what sort of emulated hardware we may have in the future - what we do is we store information about who created the virtual machine in the virtual machine configuration.  When we open a virtual machine - if we find that it was created by a different program we warn and then continue.  There is no further logic to attempt to figure out if things are okay or not.

Cheers,
Ben