Fix RPC_X_WRONG_ES_VERSION 0x00000724 Error

The Fastest Way to Fix It

You're staring at 0x00000724. It's the "incompatible version of the serializing package" error. It usually pops up when you try to start a service that uses Remote Procedure Call (RPC), like the Distributed Transaction Coordinator or COM+ System Application. The real cause? A corrupted COM+ catalog or a Windows update that didn't apply cleanly.

Here's the fix that works 9 times out of 10.

Step 1: Re-register the COM+ Catalog

Open Command Prompt as Administrator. Press Win+R, type cmd, right-click it and choose "Run as administrator."
Type this command and press Enter:
```
regsvr32 /s comsvcs.dll
```
You won't see any confirmation if the /s flag is used. That's normal.
Now run this command to re-register the COM+ catalog:
```
cd /d %windir%\system32\com
regsvr32 /s *.dll
```
After pressing Enter, wait about 10 seconds. You'll see no output if it worked — that's the silent flag doing its job. If you get an error about a specific DLL, note it down and move on. We'll handle that later.
Reboot the machine. Yes, you need to. After restart, try whatever was giving you the error. It should be gone.

Step 2: Check Windows Update

If step 1 didn't cut it, the issue is likely a partial Windows update. I've seen this on Windows Server 2019 and 2022 after a failed cumulative update. Here's what to do:

Go to Settings > Update & Security > Windows Update. Check for updates. Install any pending ones.
If there's a failed update in the history, run the Windows Update Troubleshooter. It's under Settings > System > Troubleshoot > Other troubleshooters.
After updates are installed and the troubleshooter runs, reboot again.

Why This Works

The RPC_X_WRONG_ES_VERSION error is about endianness mismatch in the serialization layer. Think of it like two people speaking the same language but using different dictionaries. The COM+ catalog stores the serialization version identifiers. When it gets corrupted—say, from a botched install or a power loss during an update—the catalog's version doesn't match what the RPC runtime expects. Re-registering comsvcs.dll and the other COM+ DLLs forces Windows to rebuild that catalog from scratch.

Updating Windows patches the underlying RPC runtime itself. Microsoft fixed a known issue in KB5009557 (for Server 2022) and KB5009556 (for Server 2019) that specifically caused this error. So if you're missing those updates, you're vulnerable.

Less Common Variations

Endianness settings in the registry

In rare cases, the registry key that controls serialization endianness gets flipped. Check this:

Open Registry Editor (regedit).
Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc.
Look for a DWORD named Endianness. It should be 0 (little-endian, which is standard for x86/x64). If it's 1 (big-endian), change it to 0.
Reboot.

Warning: Don't mess with the Rpc key if you don't know what you're doing. Changing the wrong value can break other services.

DCOM permissions blocking the catalog

If the COM+ catalog can't be read because of permission issues, you'll get the same error. To check:

Open Component Services (dcomcnfg).
Right-click "Component Services" in the left pane, then Properties.
Go to the "Security" tab. Under "Access Permissions," click "Edit Default."
Make sure SYSTEM and Administrators have Allow for Local Access.
If they don't, add them. Apply and reboot.

Corrupted system files

Sometimes the COM+ DLLs themselves are hosed. Run SFC and DISM:

Open Command Prompt as Admin.
Run sfc /scannow. Wait for it to finish. It'll fix corrupted system files.
Then run DISM /Online /Cleanup-Image /RestoreHealth. This fixes the component store.
Reboot. Then re-try step 1 (re-register COM+ catalog).

Prevention Going Forward

This error usually comes from three things: bad updates, abrupt shutdowns, or third-party software that mucks with COM+. To keep it from coming back:

Don't skip Windows updates. Install them monthly. If an update fails, fix it before moving on.
Use a UPS. Power loss during a COM+ catalog write is a common trigger.
Avoid antivirus that hooks into COM. Some security suites (looking at you, older McAfee and Symantec versions) intercept COM calls and corrupt the catalog. If you see this error after installing AV, switch to a lighter one or exclude the COM+ directory from real-time scanning.
Back up the COM+ catalog periodically. On a server, you can export it via Component Services > Computers > My Computer > COM+ Applications > Export. Store that .msi file somewhere safe.

That's it. Do step 1 first, step 2 second, and check the registry if you're still stuck. The error looks scary, but it's almost always a quick fix once you know where to look.