Hyper-V Live Migration 0x80072746 (CPU Generation Mismatch) — Bulk enabling Processor Compatibility via PowerShell?

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Hyper-V Live Migration 0x80072746 (CPU Generation Mismatch) — Bulk enabling Processor Compatibility via PowerShell?

S Kumar 30

Quick hardware mismatch headache: Live Migrations in our cluster keep crashing with Error 0x80072746 because some hosts are on different CPU generations.

I know turning on Processor Compatibility Mode fixes the CPU feature set mismatch, but what’s the cleanest PowerShell snippet or module you guys use to audit and enforce -CompatibilityForMigrationEnabled $true across all existing VMs and cluster nodes?

Want to make sure I don't miss any offline/saved-state VMs during the rollout. Thanks!

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Answer 1

Hello @S Kumar

Yes, you can audit and enable Hyper-V processor compatibility with PowerShell. The setting is per VM, not something you enable on the cluster nodes themselves.

To audit the current state:

Get-ClusterNode | ForEach-Object {
    Get-VM -ComputerName $_.Name |
        Get-VMProcessor |
        Select-Object VMName, ComputerName, CompatibilityForMigrationEnabled
}

To enable compatibility for VMs where it isn't already enabled:

Get-ClusterNode | ForEach-Object {
    Get-VM -ComputerName $_.Name |
        Get-VMProcessor |
        Where-Object { -not $_.CompatibilityForMigrationEnabled } |
        Set-VMProcessor -CompatibilityForMigrationEnabled $true
}

However, there's an important limitation: for the traditional Hyper-V processor compatibility mode, Microsoft requires the VM to be shut down before enabling or disabling compatibility mode. A saved VM isn't equivalent to a cleanly stopped VM for this change.

So for production I wouldn't blindly run the bulk Set-VMProcessor command. First generate the audit, identify the affected VMs, schedule shutdowns, apply the setting, and then restart them.

Also note that compatibility mode is intended for migration between different generations of processors from the same manufacturer. It doesn't make Intel and AMD hosts live-migration compatible.

If you're running Windows Server 2025, also look at Dynamic Processor Compatibility, which Microsoft introduced to provide more flexibility than the legacy common-feature-set approach.

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