Event log warnings every 30 seconds due to empty SessionHostConfigurationLastUpdateTime reg key

Question

Event log warnings every 30 seconds due to empty SessionHostConfigurationLastUpdateTime reg key

Rowe, Stuart 15

I have numerous AVD host pools that I administer. The hosts in each were deployed using the Host Pool wizard, so the azure agents were deployed as part of that process. Of late, I'm building out Windows 11 environments to phase out Windows 10. In doing so, I'm spending a little extra time making sure the hosts are clean.

I'm paying closer attention to the ample event log noise previously ignored. All hosts log an pair of warnings events (ID 0):

Source: Microsoft.RDInfra.RDAgent.Service.RDAgentBrokerConfiguration

Message: unable to retrieve SessionHostConfigurationLastUpdateTime from registry: System.FormatException: String was not recognized as a valid DateTime.

at System.DateTimeParse.Parse(String s, DateTimeFormatInfo dtfi, DateTimeStyles styles)

at Microsoft.RDInfra.RDAgent.Service.RDAgentBrokerConfiguration.get_SessionHostConfigurationLastUpdateTime() in C:\__w\1\s\src\RDAgent\src\Service\AgentSettings.cs:line 2746

Source: Microsoft.RDInfra.RDAgent.Service.AgentUpdateStateImpl

Message: Unexpected last recorded state

For the first event, in checking the registry (HKLM\SOFTWARE\Microsoft\RDInfraAgent) for SessionHostConfigurationLastUpdateTime, it's empty. Same on ALL hosts.

This issue is not unique to our AVD host pools. I attend some weekly Microsoft-hosted "Office Hours" themed on VDI. I brought this up to the MS folks in today's meeting. They observed the health of the agents is good. The state of the hosts in their corresponding Host Pools is 'Healthy'. No indicators to explain why this key wasn't populated upon agent installation (again, as performed by the portal wizard - no rookie user error performing the individual pieces via code). Several attendees in the meeting checked some of their respective hosts ... same issue in every case.

Here are the versions of Agents installed:

Remote Desktop Agent Boot Loader: 1.0.9023.1100 & 1.0.8925.0
Remote Desktop Services Infrastructure Geneva Agent: 46.24.3
Remote Desktop Services SxS Network Stack: 1.0.2409.29850
Remote Desktop Services Infrastructure Agent: 1.0.10673.700

The other batch of events logged at the same 30 second interval within the RemoteDesktopServices log are all Informational.

Arko 1,570 Reputation points Microsoft External Staff

2025-03-28T16:30:29.08+00:00

This is a known behavior in current Azure Virtual Desktop (AVD) agents, particularly with the SessionHostConfigurationLastUpdateTime registry key being empty, leading to repeated Event ID 0 warnings.

The Registry key atHKLM\SOFTWARE\Microsoft\RDInfraAgent\SessionHostConfigurationLastUpdateTime is expected to store a DateTime string indicating when the session host last received configuration from the AVD backend.

On many newly deployed hosts, this key is missing or empty, which causes the agent to try to parse an empty string as a DateTime — hence the System.FormatException.
The agent falls back gracefully when it fails to read this value i.e. meaning it doesn’t crash, and the host stays in a Healthy state. I believe there’s no functional impact observed on this. However we will take this as a feedback and internally share it with our product team.

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Arko 1,570 Reputation points Microsoft External Staff

2025-03-28T16:30:29.08+00:00

This is a known behavior in current Azure Virtual Desktop (AVD) agents, particularly with the SessionHostConfigurationLastUpdateTime registry key being empty, leading to repeated Event ID 0 warnings.

The Registry key atHKLM\SOFTWARE\Microsoft\RDInfraAgent\SessionHostConfigurationLastUpdateTime is expected to store a DateTime string indicating when the session host last received configuration from the AVD backend.

On many newly deployed hosts, this key is missing or empty, which causes the agent to try to parse an empty string as a DateTime — hence the System.FormatException.
The agent falls back gracefully when it fails to read this value i.e. meaning it doesn’t crash, and the host stays in a Healthy state. I believe there’s no functional impact observed on this. However we will take this as a feedback and internally share it with our product team.

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Event log warnings every 30 seconds due to empty SessionHostConfigurationLastUpdateTime reg key

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