why are you using a VM, and what are you testing with it, and how?
I gave up on using VMs because of the inability to sign into iCloud on a VM, and because it really didn't seem to save any time.
I wanted to test the first-time-install experience for our software, which seems impossible to replicate without starting with a new OS and a new user account. It seems to take just as long to reinstall the OS on a VM as it does to reinstall the OS on a physical partition. So that's what I do now - I install beta OSs on a partition of an external drive, and boot a second laptop from that (so that I can continue to use my development machine for other tasks like email and Slack).
I often need to debug behavior on the new OS, so I have to install Xcode on that new OS, which also takes its sweet time.
I put the beta OS on an external disk, and use a second laptop booted from that disk as my test machine.
I'd really like to hear how other people are using VMs for testing their software, and how that experience is better than using a separate Mac and/or a separate boot partition.