Event ID 236 on a Hyper-V server that has SR-IOV enabled on a VM in Windows Server 2016 and Windows Server 2019

Applies to: Windows Server 2019, all versionsWindows Server 2016

Symptom


On a Windows Server 2016 or a Windows Server 2019 computer that has Hyper-V role enabled, there is a guest virtual machine (VM) that is running Windows Server, and the VM has Single Root I/O Virtualization (SR-IOV) enabled. When the VM or the computer is restarted, event ID 236 is logged in the System log.

The event may have description that resemble the following:

Cause


Event 236 is logged when the user-mode process tries to allocate a virtual function before the VM and the host communication channel is established.

More information


The user mode process will retry to enable I/O Virtualization at a later stage in few moments. You can verify the IOV VF function by using the PowerShell cmdlet Get-NetAdapterSriovVf.