Windows Update Service stalls with 0x8007045E during concurrent installation requests

Likely explanation

The stall occurs when the UpdateEngine tries to serialize overlapping install requests but runs out of internal resources (handles, memory, or database transaction slots), resulting in the system error ERROR_NO_SYSTEM_RESOURCES (0x8007045E). The ConcurrentInstall warning indicates the engine detected overlapping install operations and attempted to serialize them; under heavy load this serialization logic can deadlock.

Confirmed facts

• Error 0x8007045E maps to ERROR_NO_SYSTEM_RESOURCES.
• The warning ConcurrentInstall appears in the Windows Update log before the error in reproduced cases on Windows 11 builds 22H2 and 23H2.
• Reproduction uses parallel Start-WUInstall PowerShell cmdlets.
• The contention point is believed to be the UpdateEngine’s internal transaction log or the Windows Update database (DataStore.edb) where exclusive access is required for each install; concurrent writers cause resource exhaustion.
• Administrator privileges are needed to collect logs and to test the reproduction steps; running as a standard user will not expose the same resource limits.

Steps to resolve this specific case

1. Serialize update operations – ensure only one Windows Update action runs at a time. This can be done by:
   • Using Group Policy: Computer Configuration → Administrative Templates → Windows Components → Windows Update → Allow Automatic Updates immediate installation set to Disabled (or use NoAutoUpdate with scheduled tasks).
   • Running Start-WUInstall sequentially in a script or invoking updates via the Settings UI one after another.
2. Reset Windows Update components (requires admin):

   net stop wuauserv
   net stop cryptSvc
   net stop bits
   net stop msiserver
   ren %systemroot%\\SoftwareDistribution SoftwareDistribution.old
   ren %systemroot%\\system32\\catroot2 catroot2.old
   net start wuauserv
   net start cryptSvc
   net start bits
   net start msiserver

3. Clear pending files (if any):

   del %windir%\\WindowsUpdate.log
   del %windir%\\Logs\\WindowsUpdate\\* /s

4. Verify resource availability – before reproducing, open Process Explorer and check the handle count of the svchost.exe process hosting wuauserv. A steady increase during concurrent installs signals exhaustion; after applying the serialization step, the handle count should stay stable.

Missing diagnostic detail that would change the recommendation

Do you see the ConcurrentInstall warning in the WindowsUpdate.log immediately before the 0x8007045E error? If the warning is absent, the stall may stem from a different resource limit (e.g., system‑wide handle or memory pressure) and you should collect a memory dump of the UpdateEngine and analyze for deadlocks or leaks instead of focusing solely on serialization.