qemu-aarch64-softmmu: Number of SMP CPUs requested (10) exceeds max CPUs supported by machine 'mach-virt' (8)

[anaghmirji]

Describe the issue
When running the VM I get the error message "qemu-aarch64-softmmu: Number of SMP CPUs requested (10) exceeds max CPUs supported by machine 'mach-virt' (8)"

Configuration

• UTM Version: 2.3.1(38)
• OS Version: MacOS 12.0.1
• Apple Silicon - M1Pro 10CoreCPU,16core GPU

Debug log
debug.log

[DrewManto]

I noticed this also. By default I believe it tries to assign all cores to the vm which is 10(macbook Pro M1 and M1 Max but for some reason it does not work and spits this error out. Just override how many CPU's to pass to the VM and it will work fine.

[anaghmirji]

I noticed this also. By default I believe it tries to assign all cores to the vm which is 10(macbook Pro M1 and M1 Max but for some reason it does not work and spits this error out. Just override how many CPU's to pass to the VM and it will work fine.

Yes it works now.... Thanks a lot :)

[anaghmirji]

I noticed this also. By default I believe it tries to assign all cores to the vm which is 10(macbook Pro M1 and M1 Max but for some reason it does not work and spits this error out. Just override how many CPU's to pass to the VM and it will work fine.

But for some reason while I'm setting it up the cursor suddenly stops working and I cannot continue further, this is happening every time I'm trying to set the VM

[DrewManto]

turn off force multicore if you have it enabled.

[osy]

UTM -> Preferences there’s an option to only use performance cores.

[oaklandgit]

Thanks all. This worked for me on my M1 Macbook Pro 14"

To summarize:

1. Go to the virtual box's settings: System > Show Advanced Settings > enter 8 CPU Cores and make sure Force Multicore is unchecked
2. Go to UTM preferences and check "use only performance cores by default"

After starting the VM and selecting "Install Ubuntu Server" there was quite a delay but it eventually kicked in. Then I continued to follow the instructions here:

https://mac.getutm.app/gallery/ubuntu-20-04

Good luck!

[conath]

Duplicate of #3180

[smukahhal]

The following worked with me :

• Go to Setting -> System - Check Show Advance Settings.
• A CPU Cores, I put 8.
• Saved and start the VM.
  Worked with any issues.

[TheBigSasha]

I had the same issue, limited CPU cores to 8 and the VM works.