Fix COMADMIN_E_REGDB_NOTOPEN (0x80110473)

Quick answer

Restart the COM+ System Application and Windows Management Instrumentation services. If that doesn't help, delete the corrupt transaction log file at %SystemRoot%\system32\com\dcom\compluslog.pol.

Why this happens

This error pops up when you try to open Component Services (dcomcnfg.exe) or run a script that uses the COM+ catalog. What's actually happening here is that the COM+ registry database — a file-based catalog at %SystemRoot%\system32\com\dcom\ — gets locked or corrupted. The most common trigger is a failed Windows update that restarts the COM+ System Application service while it's mid-write. I've also seen it on Windows Server 2022 after an unexpected power loss. The database isn't like SQL Server; it's a lightweight proprietary store that uses memory-mapped files. When the lock is stale or the log file is corrupt, it refuses to open.

Fix steps

Open Services.msc — hit Win+R, type services.msc, press Enter.
Stop the COM+ System Application — find it in the list, right-click, and choose Stop. If it's already stopped, skip ahead.
Stop Windows Management Instrumentation — this service is a dependency. COM+ won't release its lock if WMI is still using it. Stop WMI, but leave it on Manual start.
Rename (or delete) the corrupt log file — open an admin Command Prompt and run:
```
cd /d %SystemRoot%\system32\com\dcom
ren compluslog.pol compluslog.pol.old
```
The reason step 3 works is that COM+ rebuilds this log file cleanly when it starts fresh. If you just restart the services without deleting it, the old corrupt lock persists.
Start Windows Management Instrumentation — back in Services.msc, start WMI and wait 10 seconds for dependencies to initialize.
Start COM+ System Application — start this one last. Check that it shows a status of "Running."
Test it — open Component Services (dcomcnfg.exe) or run regsvr32 /i comsvcs.dll from an admin prompt.

Alternative fixes if step 3 doesn't work

Check the DTC (Distributed Transaction Coordinator) — if your COM+ app uses distributed transactions, the DTC service might be stuck. Run msdtc -uninstall then msdtc -install from an admin prompt. Reboot. This is rare on single-machine setups but common in cluster environments.
System File Checker — corrupt system files can mimic this error. Open cmd as admin and run sfc /scannow. I've seen it fix nothing 90% of the time, but the 10% saves you a reinstall.
Check the Event Viewer — look under Windows Logs > Application for Event ID 4199 or 4754. If you see "COM+ registry database file is corrupt," the log file deletion above is your only path.

Prevention tip

Don't let Windows updates or group policy changes run while Component Services is open. The COM+ catalog is single-writer. If a background task tries to reconfigure it (like a .NET component registration during an update) while you're poking around, it'll corrupt the lock file. Close dcomcnfg.exe before you install updates, and set the COM+ System Application service to Manual start (not Disabled) so it only loads when needed.