It is important to do not create snapshots regarding Palo Alto VM-Series firewall on virtualized environment, here it is relative article and section
"The VM-Series firewall functionality is very similar to the Palo Alto Networks hardware firewalls, but with the following limitations:
- Do not use the VMware snapshots functionality on the VM-Series on ESXi. Snapshots can impact performance and result in intermittent and inconsistent packet loss.See the VMware best practice recommendation for using snapshots.If you need configuration backups, use Panorama, or from the firewall, use Export named configuration snapshot (Device > Set up > Operations). Using Export named configuration snapshot exports the firewall’s active configuration (running-config.xml) and allows you to save it to any network location."
