CO_E_INIT_RPC_CHANNEL 0x8000400A: RPC service won't start

When this error shows up

You're on a Windows 10 or Windows Server 2019 box, maybe after a recent cumulative update. Or you just cleaned up your startup with CCleaner or Autoruns. Suddenly Outlook won't connect, or SQL Server throws a fit. You check Event Viewer – there it is: CO_E_INIT_RPC_CHANNEL (0x8000400A). The RPC service just won't initialize.

I've seen this most often after a Windows Update that partially failed, or after someone disabled RPC in Group Policy thinking it was a security risk. It can also happen after a registry cleaner removed what it thought were orphaned keys. Don't panic – it's fixable.

What's really going on

The error code 0x8000400A means the Remote Procedure Call (RPC) service, RpcSs, can't start. That service is the backbone for all sorts of Windows communication – file sharing, printing, Active Directory, you name it. The root cause is almost always one of these three:

• The RPC service itself is disabled or set to manual when it needs to be automatic.
• A registry key under HKLM\SYSTEM\CurrentControlSet\Services\RpcSs is missing or corrupted.
• Another required service – like DCOM Server Process Launcher – isn't running.

Sometimes a group policy has disabled RPC. Sometimes a malware cleanup tool removed the service entry. Let's walk through the fix.

Step-by-step fix

Step 1: Check the RPC service status

1. Press Win + R, type services.msc, hit Enter.
2. Scroll down to Remote Procedure Call (RPC). It should show Running and Startup type: Automatic.
3. If it's not running, right-click it and choose Start. If it's set to Manual or Disabled, right-click > Properties, set Startup type to Automatic, then click Apply and OK.
4. Also check these two services – they need to be running too:
   • DCOM Server Process Launcher – set to Automatic, should be running.
   • RPC Endpoint Mapper – set to Automatic, should be running.

After you change the startup type, you should see the service start within a few seconds. If it starts but then stops, move to Step 2.

Step 2: Repair the registry entry

The real fix, in my experience, is a corrupted registry key. Here's how to fix it.

1. Launch Registry Editor – press Win + R, type regedit, hit Enter.
2. Go to this path:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RpcSs
3. If the key is missing entirely (you see nothing under Services named RpcSs), you have bigger problems – skip to Step 3.
4. If the key is there, look at the Start value. It should be 2 (for Automatic). If it's 3 (Manual) or 4 (Disabled), double-click Start, set it to 2, click OK.
5. Also check the ImagePath value. It should be:
   C:\Windows\system32\svchost.exe -k rpcss
   If it's missing or wrong, you'll need to create or fix it. To create it: right-click blank space > New > Expandable String Value, name it ImagePath, set the value to the path above.
6. Close Registry Editor and restart the computer. After reboot, check the service again.

Step 3: If the registry key is missing

If RpcSs doesn't exist under Services at all, someone or something deleted it. You need to recreate it manually. This is a bit tedious but works.

1. In Registry Editor, navigate to HKLM\SYSTEM\CurrentControlSet\Services.
2. Right-click Services, choose New > Key. Name it RpcSs (exactly, case doesn't matter but spelling does).
3. Inside the new RpcSs key, create these values (right-click blank space, choose New):
   • DWORD (32-bit) named Start, value 2.
   • DWORD (32-bit) named Type, value 16 (this means Win32 service).
   • DWORD (32-bit) named ErrorControl, value 1.
   • Expandable String Value named ImagePath, value C:\Windows\system32\svchost.exe -k rpcss.
   • String Value named DisplayName, value Remote Procedure Call (RPC).
   • String Value named ObjectName, value NT AUTHORITY\NetworkService.
   • String Value named Description, value Serves as the RPC endpoint mapper and COM Service Control Manager. If this service is stopped or disabled, programs using COM or RPC will not work properly.
   • DWORD (32-bit) named DelayedAutoStart, value 0.
4. Now also create a subkey under RpcSs called Security. Right-click RpcSs, New > Key, name it Security. Inside that, create a Binary Value named Security – you can leave it empty for now, Windows will populate it.
5. Restart the computer. After reboot, the RPC service should start automatically.

What if it still fails?

If the error persists after these steps, check these things:

• Group Policy – run gpedit.msc, go to Computer Configuration > Windows Settings > Security Settings > System Services. Find Remote Procedure Call (RPC). It should be set to Automatic. If it's Disabled or Not Configured, change it to Automatic and reboot.
• SFC / DISM – open Command Prompt as admin, run sfc /scannow, then DISM /Online /Cleanup-Image /RestoreHealth. Corrupted system files can mess with RPC.
• Malware scan – run a full scan with Windows Defender or Malwarebytes. Some infections kill RPC to hide.
• Check for pending updates – go to Settings > Update & Security > Windows Update. If there's a failed update, run the Windows Update Troubleshooter, then try installing the update again.

If none of this works, you're looking at a repair install or a clean install of Windows. But I've fixed dozens of these with just the registry repair above – it's the real fix nine times out of ten.