Abstract: In many circumstances, it is advantageous to backup the data for a VM while it is in operation. Traditionally, this is accomplished by taking a snapshot of the VM while it is running. After a snapshot has been created, the preserved data is typically referred to as the base disk. The base disk can then be used to create a consistent backup. The hypervisor on which a VM is running can sometimes be used to create a snapshot, but not all virtualization platforms allow access to the base disk after the hypervisor has created the snapshot. The present disclosure features a method for creating a backup for a virtual machine while it is operating through the use of a snapshot and a differencing disk.