Both VMs show the same symptom from the outside: black screen, VM appears to be running, no
console output. The host logs show them stopping at two different points. Posting the
observations rather than guesses, in case the timings are useful for triage.
A third VM created new under 27.0.0 has not failed once.
VM A stops before
screen, and the log recorded no further guest activity.
Under 26.4.1, nested virtualization on:
Under 27.0.0, nested virtualization on: six attempts (10:35:39, 10:36:23, 10:37:16, 10:37:38,
11:13:27, 11:14:20). All six reached
other guest output, for as long as I left them running.
I then shut the VM down and changed one setting, nothing else:
Under 27.0.0, nested virtualization off:
Same disk, same kernel, same firmware build. It has been running normally since.
Attempts recorded in parallels.log for this VM:
logs
the morning; the hangs continued at the same rate afterward.
Actions > Reset while it is hung usually reaches the kernel on the first or second try.
console output. The host logs show them stopping at two different points. Posting the
observations rather than guesses, in case the timings are useful for triage.
A third VM created new under 27.0.0 has not failed once.
Environment
- MacBook Pro, Apple M4 Max
- macOS 26.6.2
- Parallels Desktop 27.0.0 (58628), upgraded from 26.4.1 (57516) on the morning of these logs
- VM A: Debian 12.11 ARM64, GRUB, nested virtualization off, Secure Boot off
- VM B: Gentoo, systemd-boot, 14 CPU / 64 GB RAM, "Other Linux"
profile, nested virtualization on at the time of the failures, Secure Boot off - VM C: Debian 13.6 ARM64, created new under 27.0.0, no failures
Log lines I used as markers
From~/Parallels/<name>.pvm/parallels.log:
Code:
Virtual machine is ready to boot! firmware started
VCPU0: OnExitBootServices() firmware handed control to the kernel
[NET0][VIRTIO] AckFeatures (host_feat:...) guest kernel brought up virtioOnExitBootServices(). VM B reaches it and produces nothing after it.VM B
The systemd-boot menu always appeared and was responsive. Selecting a kernel entry blanked thescreen, and the log recorded no further guest activity.
Under 26.4.1, nested virtualization on:
| Date/time | OnExitBootServices | First virtio | Result |
|---|---|---|---|
| 08-29 16:27 | 16:27:52.600 | 16:27:53.330 | booted |
| 08-30 19:48 | 19:48:56.517 | 19:48:57.071 | booted |
| 08-31 11:17 | 11:17:09.994 | 11:17:10.598 | booted |
Under 27.0.0, nested virtualization on: six attempts (10:35:39, 10:36:23, 10:37:16, 10:37:38,
11:13:27, 11:14:20). All six reached
OnExitBootServices(). None produced a virtio line or anyother guest output, for as long as I left them running.
I then shut the VM down and changed one setting, nothing else:
Code:
prlctl set <vm-name> --nested-virt off| Date/time | OnExitBootServices | First virtio | Result |
|---|---|---|---|
| 09-01 11:17 | 11:17:33.636 | 11:17:33.960 | booted, desktop up in about 15s |
VM A
Start attempts hang with "Virtual machine is ready to boot!" in the log and noOnExitBootServices() afterward. No boot menu is drawn, and the VM sits there indefinitely.Attempts recorded in parallels.log for this VM:
- Under 26.x: 5 attempts, 5 handoffs to the kernel, no hangs.
- Under 27.0.0 on upgrade day: 15 attempts, 7 handoffs, 8 hangs at this stage.
<VirtualizedHV>0 in config.pvs), and every startlogs
[SecureBoot] Status: off. Parallels Tools were updated to 27.0.0-58628 partway throughthe morning; the hangs continued at the same rate afterward.
Actions > Reset while it is hung usually reaches the kernel on the first or second try.