Hi,
No, it's not related to Parallels or any other 3rd party App. The MobileBackup is a sparsebundle disk used by Time Machine on OS X Lion (not present in Snow Leopard and before). And, moreover, it's only present on notebook computer once you activate Time Machine. So you have certainly a Macbook Air/Pro running OS X Lion with TimeMachine enabled
.
To be honest, i think this functionality is useless for most people and should be disable. You can do it by opening Terminal application and type: sudo tmutil disablelocal. Time Machine will continue to work on external Volumes. If you want to re-enable it: sudo tmutil enablelocal.
edit: By the way, don't forget to exclude virtual machines from backups (in TM config panel or in the VM Settings).
Regards,
Didier
Last edited: May 11, 2012