I vmotioned a VM today, 2008 R2, and HP SIM sent an unreachable shortly after. This happens sometimes when we vmotion as a ping packet is dropped. Didn't think anything of it, but the owner noticed they were disconnected and couldn't get back on. Turns out it was rebooted apparently due to sysprep running on it and becoming disjoined from the domain.
Looking at the task/events in vsphere I see this 4 seconds after the vmotion finished;
Started customization of VM. Customization log located at C:\Windows\TEMP\vmware-imc\guestcust.log in the guest OS.
3 minutes later
Customization of VM succeeded. Customization log located at C:\Windows\TEMP\vmware-imc\guestcust.log in the guest OS.
The user associated with it just shows as "User" not an actual named user account. How or why would this happen? I don't recall this ever happening, but I'd obviously like to prevent it from happening again if it was a result of anything I did.