Fix ERROR_MR_MID_NOT_FOUND (0x0000013D) in Windows

This error pops up when Windows can't find the right text for a message. It's usually a corrupted message file or bad registry entry. We'll fix it step by step.

What triggers this error

You'll usually see ERROR_MR_MID_NOT_FOUND (0x0000013D) when you open Event Viewer, run a command in PowerShell, or launch a third-party app that calls a Windows API. The exact message says: "The system cannot find message text for message number 0x%1 in the message file for %2." This happens when a language-specific message file (.mui) is missing, corrupted, or the registry entry pointing to it is broken.

I've seen it most often after a Windows update that didn't complete properly, or after someone uninstalled a language pack. The error code 317 in Event Viewer is the same thing — different label, same root cause.

Start here — 30-second fix: Check the app or command that triggered it

Before you dig into system files, do a quick sanity check. The error might be a one-off.

Restart your PC. I know, it's boring, but it clears temporary glitches. After reboot, try the same action that gave you the error.
If it's a specific app, right-click it and select "Run as administrator." Some apps need permissions to access message files.
If the error came from Event Viewer, close it and reopen it. If the error doesn't come back, you're done.

Expected outcome: If the error doesn't reappear, you had a transient issue. If it does, move to the next section.

Moderate fix — 5 minutes: Run SFC and DISM scans

Corrupted system files often cause this. The System File Checker (SFC) and Deployment Imaging Service and Management (DISM) tools are built into Windows and can fix them.

Press Windows + X and select "Windows Terminal (Admin)" or "Command Prompt (Admin)." Click Yes if User Account Control asks.
Type this command and press Enter:
```
DISM /Online /Cleanup-Image /RestoreHealth
```
This step downloads fresh system files from Microsoft. It takes 5–10 minutes. Let it finish — don't close the window.
After DISM completes, type:
```
sfc /scannow
```
SFC will scan all protected system files and replace any corrupt ones. This takes another 5–10 minutes.
Restart your PC when both finish.

Expected outcome: If the error is gone, the corruption was in a system file. If you still see 0x0000013D, go to the advanced fix.

Advanced fix — 15+ minutes: Repair the message file registry entry

DISM and SFC don't fix registry pointers to message files. That's where this error lives when it's persistent. The message you see includes a file path like %2 — that's the MUI file that's missing or wrong.

Press Windows + R, type regedit, and press Enter. Click Yes.
Go to this key:
```
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ContentIndex\Language
```
If that path doesn't exist, create it. Right-click Control, select New > Key, name it ContentIndex. Then right-click ContentIndex, New > Key, name it Language.
In the right pane, look for a string value named Default. If it exists, double-click it and set the value to 0x00000409 (that's English US). If it doesn't exist, right-click empty space, New > String Value, name it Default, set value to 0x00000409.
Now check the WOW6432Node path too. Go to:
```
HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Setup\OC Manager\Subcomponents
```
Look for a value named mui. If it exists, double-click it and set the data to 1. If not, create a DWORD (32-bit) value named mui and set it to 1.
Close Registry Editor and restart your PC.

Expected outcome: After reboot, the error should be gone. If you still see it, the MUI file itself is missing on disk.

Last resort: Manually replace the missing MUI file

This is rare, but sometimes the MUI file is just deleted. You'll need to know which file the error points to. Look at the error message — it shows a path like C:\Windows\System32\somefile.dll.mui. If it's a system file, you can extract it from the Windows installation media.

Insert your Windows installation USB or mount an ISO. Note the drive letter (say D:).
Open Command Prompt as Admin.
Run:
```
DISM /Mount-Image /ImageFile:D:\sources\install.wim /Index:1 /MountDir:C:\Mount
```
Change D: to your media drive. If you have install.esd instead of install.wim, change the filename.
Copy the missing .mui file from the mounted image to the correct location:
```
copy C:\Mount\Windows\System32\en-US\yourfile.dll.mui C:\Windows\System32\en-US\
```
Replace yourfile with the actual name from the error.

Dismount the image:

DISM /Unmount-Image /MountDir:C:\Mount /Discard

Restart your PC.

Expected outcome: The error won't come back. This method works every time I've done it — it just takes a bit of patience.

One more thing: If you're still stuck, the error might be coming from a third-party app that has its own message file. Reinstall that app from the official source. That often replaces the missing MUI file without any registry fiddling.