Cannot open macOS VM - limit exceeded

[markbattistella]

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Describe the issue

I have searched the previous issues and found nothing about the VM limits for running macOS on UTM. As I understand there is a hard limit imposed by Apple to not allow more than 2 macOS VMs to run.

The issue I face is that when I shutdown my VM via the VM system, and UTM lists the VM as offline, I can still not re-launch it.

I receive the error:

Error
The number of virtual machines exceeds the limit. The maximum supported number of active virtual machines has been reached.

I have no other VMs running, I have quit the UTM app, and even checked Activity Monitor. The only way to reset the "count" is a system reboot.

I haven't been able to find anything on fixing this, or if there is an issue at the moment with the way shutting down doesnt minus a count number.

Configuration

• UTM Version: 4.3.5(87)
• macOS Version: 13.4.1 (c)
• Mac Chip (Intel, M1, ...): MacBook Pro M2 Max

[ideologysec]

Is Virtual Machine Service still running? This is the actual process that runs the virtual machine. If you force quit that, does the issue resolve?

[markbattistella]

@ideologysec so I waited for the issue to occur again.

But, after using the VM all day yesterday today it now reports the error message.

Chronology

2023-08-18:

• Used the macOS VM all day, internally rebooted a few times. No issues whatsoever

Notes:

• physical mac machine did not go to sleep
• physical mac machine did not have lid closed
• physical mac machine did have screen go off / black throughout day

2023-08-18:

• End of day, shutdown the macOS VM internally
• Quit the UTM app
• I put physical mac to sleep and closed the lid

2023-08-19:

• Launch UTM, and tried to boot the macOS VM
• Error message appears
• Check activity monitor: no Virtual Machine Service present, UTM app is present

Notes:

• attempted to sleep physical mac to replicate issue: did not seem to cause issue
• attempted to close lid on physical mac to replicate issue: did not seem to cause issue
• attempted to sleep and close lid on physical mac to replicate issue: did not seem to cause issue

---

At this point I can't replicate it, it just occurs at times without any UTM or Virtualisation services running.

I don't have any knowledge on collecting logs or ways to see what is occurring when I get the error message.

[runwaygoats]

https://kb.parallels.com/128867

running more than two such VMs simultaneously is impossible.

Needs to be verified if this is an Apple Virtualization Framework limit.

[ideologysec]

Yes. Apple has hardcoded into the released OS' a check for how many macOS VMs are running at one time.

Here's a technical deep dive with more info: https://khronokernel.github.io/macos/2023/08/08/AS-VM.html

[howieisaacks]

For me, this is happening when NONE of my VMs are already running. It's now affecting both UTM and Parallels.

[pthexton]

This is the same issue as I raised with #4257 - I would suggest there may be other issues reported that are also basically the same problem and maybe a bit of house cleaning is needed to merge them / close duplicates.

Anyhow, as far as I've been able to tell the Mac firmware tracks the active number of VMs somehow but somewhere along the line this tracking gets it wrong and it thinks there are still macOS Guest VMs running even though there aren't.

When I do run in to this issue (very rare now as I use the CLI tart utility instead of using UTM where I don't seem to run in to this problem), the easiest solution I've found is to log off the mac and back in again (a full reboot isn't required)

[danik85sh]

Same issue here with M1 MacBookPro running UTM 4.4.5(94) on MacOS Sonoma 14.4.

Restart/Log Out solves it, but it totally disturbed the dev process.