A backup for virtual machine cannot be created:
[root@vz ~]# prlctl backup VMName Failed to backed up the VM: Unable to create a backup copy of the virtual machine "VMName" (PRL_ERR_FREE_DISK_SPACE_FOR_CREATE_SNAPSHOT). Please try again. If the problem persists, contact your system administrator for assistance.
Insufficient space on a partition, where the virtual machine is stored.
Free space on a partition, where the virtual machine is stored.
In order to locate a virtual machine's home directory, execute the following command:
[root@vz ~]# prlctl list -i VMName | grep Home Home: /var/parallels/VMName.pvm/