Virtual Machine Management Service fails to start

Upgrade the VMM server from build 10.25.1200.0 to VMM 2025 Update Rollup 1 (UR1) because the installed build is the original VMM 2025 release, while SQL Server 2025 support is included with UR1.

Install VMM 2025 UR1

Your current vmmservice.exe version, 10.25.1200.0, is the VMM 2025 GA build. UR1 is cumulative, so intermediate updates are unnecessary; after UR1, the expected VMM build is 10.25.1439.0.^1^

1. Back up the VMM database in SQL Server before applying the update.
2. Obtain both UR1 packages:
   • VMM Server: KB5068308
   • Administrator Console: KB5068702
3. On the VMM management server, install the server update first from an elevated command prompt:

      msiexec.exe /update kb5068308_vmmserver_amd64.msp
   

4. Install the Administrator Console package on the VMM server and on every computer where the console is installed. The server and console components should remain at compatible update levels.
5. Restart the VMM server if requested.
6. Confirm that System Center Virtual Machine Manager starts and that vmmservice.exe reports build 10.25.1439.0.

Microsoft documents separate server and console packages, the manual installation command, and SQL Server 2025 support in UR1.^2^ Microsoft also recommends bringing VMM 2025 installations to UR1 before applying fixes delivered on top of that rollup.^3^

If the service still crashes

The Application Error entry only identifies an unhandled managed-code exception; it does not expose the underlying exception. Retrieve the corresponding events from:

• Event Viewer → Applications and Services Logs → Microsoft → VirtualMachineManager → Server → Operational
• Event Viewer → Windows Logs → Application, especially .NET Runtime events near the crash time
• Any report path shown in VMM Event ID 5004, commonly below C:\ProgramData\VMMLogs

Look for the full exception name and stack trace.

If the operational log shows ReflectionTypeLoadException, verify that both the VMM Server and Administrator Console packages were installed at compatible levels. Microsoft documents mismatched server/console updates as a cause of this specific startup exception.^4^

If the logs still do not identify the failure, capture the unhandled exception with ProcDump:

mkdir C:\procdump
cd /d C:\procdump
procdump.exe -ma -e vmmservice.exe
sc start SCVMMService

For first-chance exceptions:

procdump.exe -ma -e 1 -t -n 10 vmmservice.exe
sc start SCVMMService

The dump is written under C:\procdump and can be supplied to Microsoft Support with the VMM operational log and matching .NET Runtime event.^5^

Do not modify the VMM database or reinstall .NET based only on exception code 0xe0434352; the complete exception and stack trace are needed before choosing either action.

References

1. System Center – Virtual Machine Manager build versions
2. Update Rollup 1 for System Center 2025 Virtual Machine Manager
3. Release notes for System Center Virtual Machine Manager
4. VMM service doesn't start and returns ReflectionTypeLoadException after you apply an update rollup
5. How to use ProcDump to troubleshoot Virtual Machine Manager service (Vmmservice.exe) issues