In the knowledge base it recommends Shutting Down a VM before backing up. https://kb.parallels.com/en/4859 But is it sufficient to SUSPEND it? (Since presumably all states in RAM are committed to hard drive.)
No, it's not safe. The guest OS in VM is running and its states may not be committed to virtual disk. Also such backup can not be resumed on other Mac if some CPU features differ. In this case hard reset of VM will be required. Another point is that it required to backup image of guest OS RAM, so it's waste of time and disk space.
Many thanks @mmika , in future I'll shutdown Windows before performing CarbonCopyCloner backups of the VM. (And will remember your advice!) Since OSX only gets restarted perhaps once every 2-3 months on my laptop (despite very heavy usage - it's remarkable) it's quite painful how often - for one reason or another - Windows gets shutdown / rebooted.
