The event description for the subject behavior is similar to:
The device 'Manufacturer Model (C) SCSI Disk Device' (SCSI\Disk&Ven_Vendor&Prod_Product_(C)Vendor&Rev_2001\4&13376f61&0&1017) disappeared from the system without first being prepared for removal.
Windows Server 2003 identifies the hardware volume shadow copy object the same way that it identifies a hard disk object. When you delete a hardware volume shadow copy object, you get the same error that is generated when you remove a hard disk.
If you deleted the hardware volume shadow copy object, you can ignore this event.