Reports indicate this was fixed in macos 15.8.2 and 26.7.2

"update causes the virtual machine to black screen upon reboot during the installation." Maybe... It sounds different though.

https://feedbackassistant.apple.com/feedback/25033429

This is a huge problem. We have a service provider blocked due to https://developer.apple.com/forums/thread/848707 and needs to get on the latest 26 VM version for security updates. Yet, there is no public IPSW for 26.7.1 now that 27.x is out. Can we get some pressure on Apple providing ALL IPSW files for VMs, no matter if newer major versions are out?

We see this with all other Virtualization tools as well. Affects several of our customers. VM just becomes unresponsive post-inner VM upgrade of macOS.

Customer support also didn't know what to do or how to reach legal

That's sort of what I'm confused about. I go to that page and there is, as far as I can tell, and I could be blind, no way to submit a request to the legal team for EULA stuff. It just takes me to normal support or other options that are unrelated to EULA requests. :( Do I use the "Rights and Permissions" and they then forward it to the right people? Sorry, just a bit lost due to the complexity of the legal/support page.

Do you know the way to reach Apple's legal team?

Wow you're right. I must have already had two VMs running on the host I was testing on. Regardless, I need to know the legal path to communicate this interest with Apple and get official approval.

Howdy Quinn! Virtualization.Framework has a hard cap at two per machine. If I'm running containers that use Virtualization.Framework and then try to start a VM with any of the virtualization tools out there, it fails saying exceeded maximum. As of right now customers of our need to run these containers on linux machines on the side and that can be extra headache. I'd love to see if they have, finally in 27, a path to get this unblocked on the host and run more than two instances at a time.

We hit userspace watchdog panics (logd unresponsive on firehose I/O) during sustained writes into a large APFS file that was created with clonefile and then overwritten at many offsets. The workload was high-rate, relatively small pwrites with F_NOCACHE (and F_NODIRECT) on the clone. That behaved like sparse/COW allocation pressure even though the logical file size looked fully populated. Only reproducible on 2TB AP2048Z SSD. Couldn't get it to panic on any other type of hardware we have :( We understand clone + overwrite implies COW extent work similar to sparse writes. We’re mainly sharing this as a data point: under prolonged high-IOPS uncached pwrite into a clone, APFS metadata / system services (esp. logd/firehose) can fall far enough behind to trip the userspace watchdog, and the failure mode is easy to misread as a 'preallocated file should be fine' thing. Unfortunately we had to use customer hardware don't have any 2TB drives, but two customers did) and they won't allow us to share anything else. If it changes, I'll submit a feedback report. Otherwise we can just close this. I found a way to work around it. Thanks!

Is there a way to disable logd to test around it? We tried log config --mode "level:off" but it didn't seem to prevent the panic. We're actually using F_PREALLOCATE already which is what's so odd about this.

Some other logs to understand what we're seeing: com.apple.logd.store in TH_WAIT | TH_UNINT for ~120–200s com.apple.firehose.drain-io / io-wl blocked behind it then watchdog: no logd checkins for 120s userspace watchdog timeout: no successful checkins from logd ... 120 seconds unresponsive dispatch queue(s): com.apple.firehose.io-wl

Both my dev and I confirmed 26.6b3 host OS with not only a pre-existing broken Xcode 27 beta 2 install upgraded to Xcode 27 beta 3, but also no Xcode beta 27 installed at all being installed after the 26.6b3 install. Both work fine now with Anka.

I'll be trying upgrading my broken Xcode 27 beta 2 installed host machine to 26.6b3 today once things calm down and and test it out. But yeah, testing the install 26.5, upgrade, then install Xcode 27 beta (without ever having it on the machine) is also a great idea