Fix EPT_NT_INVALID_ENTRY (0XC0020034) on Windows

You're working away and suddenly a program throws error 0XC0020034 — EPT_NT_INVALID_ENTRY. This usually hits when you're trying to connect to a remote service or start a local app that relies on RPC (Remote Procedure Call). I've seen it most often after a Windows update or when an app installer crashes mid-way. For example, a user tried to launch a custom database client and got this error every time — the database's RPC endpoint had gone missing.

What causes it?

The error means the RPC Endpoint Mapper can't find a registered endpoint for the interface you're calling. Think of an endpoint like a phone number — the RPC mapper is the phonebook. If the number's missing or scrambled, the call fails. Why does it happen? Common triggers:

A service that registered an endpoint crashed and didn't unregister properly.
Registry entries for RPC interfaces got corrupted — often from a failed software install.
Another app or malware hijacked the RPC endpoint mapper's port (135).

The real fix is to clean up the stale entries and restart the mapper. Here's how.

Fix for 0XC0020034

Open Registry Editor. Press Win + R, type regedit, hit Enter. Click Yes if UAC asks.
After opening, you should see the Registry Editor window with a tree on the left.
Back up the registry first. Go to File > Export. Choose a location, name it something like "backup-before-rpc-fix", and save. This is your safety net — if something goes wrong, you can double-click this file to restore.
Navigate to the RPC interface key. In the left pane, expand this path:
```
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc\ServerEntry
```
If the key doesn't exist, skip to step 5. If it does, you'll see subkeys with GUID names under it — those are registered interfaces.
Delete orphaned entries. Look for subkeys that point to services you no longer have. For example, if you see a GUID referencing a program you uninstalled, right-click that subkey and choose Delete. Confirm Yes. Don't delete everything — only entries you're sure are stale. If you're unsure, skip this step.
After deleting, the subkey should disappear from the list.
Restart the RPC services. Press Win + R, type services.msc, hit Enter. Find these three services:
- Remote Procedure Call (RPC)
- RPC Endpoint Mapper
- DCOM Server Process Launcher
Right-click each one and choose Restart. Do them in this order: Endpoint Mapper first, then RPC, then DCOM.
After each restart, you'll see the status change to "Running" again. Wait 10 seconds between each restart.
Flush DNS and reset winsock. Open Command Prompt as administrator (search cmd, right-click, "Run as administrator"). Run these commands one at a time, pressing Enter after each:
```
ipconfig /flushdns
netsh winsock reset
netsh int ip reset
```
Each command will show a success message. The last one may ask you to reboot — say yes.
Reboot your machine. Click Start > Power > Restart. This ensures all changes take effect.
After reboot, try the app that was failing. The error should be gone.

If it still fails

If the error persists, a few things to check:

Check for port conflicts. Open Command Prompt as admin and run netstat -ano | findstr :135. If anything other than the RPC Endpoint Mapper (PID usually 4 or 700-ish) shows up, you've got a conflict. Kill that process with taskkill /PID [number] /F, then restart the RPC services again.
Run System File Checker. In an admin cmd, run sfc /scannow. Let it finish — it'll replace corrupted system files if any. This takes 10-15 minutes.
Check for malware. Some malware specifically targets RPC endpoints. Run a full scan with Windows Defender or your AV of choice.
Last resort — In-place upgrade. If nothing works, run the Windows 10/11 installer from inside Windows (download from Microsoft's site). Choose "Keep personal files and apps". This reinstalls the OS core without wiping your data. I've seen this fix stubborn RPC issues that nothing else could touch.

That's it. The 0XC0020034 error is stubborn but not impossible. Just follow the steps in order — skipping the backup step is the only thing that'll bite you later.