Remote Desktop Service Error 126 Module not found

When you attempt to start the Remote Desktop Services (“TermService”) service, Error 126 may occur. Here’s the complete error message:

Windows could not start the Remote Desktop Services service on Local Computer.

Error 126: The specified module could not be found.

Cause

The error occurs if the file termsrv.dll is missing or corrupted. Another reason could be that the Remote Desktop Services ServiceDLL may be pointing to a third-party module, such as “%ProgramFiles%\RDP Wrapper\rdpwrap.dll” (“RDP Wrapper.”)

The RDP Wrapper’s .msi file is broken. It doesn’t install or uninstall the app correctly. The following error is shown:

There is a problem with this Windows Installer package. A program required for this install to complete could not be run. Contact your support personnel or package vendor.

As a result, the uninstallation procedure is not proper. The entry remains in the program listing.

Resolution

To resolve the Remote Desktop Services (“TermService”) service error 126, follow one of the methods below:

Option 1: Uninstall “RDP Wrapper” properly

1. Download the RDP Wrapper setup .zip file from the following link:

   https://github.com/stascorp/rdpwrap/releases

2. Unzip and extract the archive to a folder.

   

3. Run Uninstall.bat, and click Yes when asked for elevation consent.
4. Download MicrosoftProgram_Install_and_Uninstall.meta.diagcab from Microsoft. (Source: Microsoft.)

   (If Microsoft Edge or Chrome mislabels the above file as PUA/malware, choose to keep it by tapping “…” in the bottom bar, choosing Keep, and then choosing Keep anyway in the dialog that appears.)

5. Run the .diagcab file you downloaded. Click Next.

   

6. In the next screen, click “Uninstalling”.

   

7. Select “RDP Wrapper Library”, and click Next.

   

8. Click Yes, try uninstall.

   

   This cleanly uninstalls “RDP Wrapper” and restores the original ServiceDLL entry in the registry.

9. To delete the “RDP Wrapper” entry in Apps & Features or Programs and Features, open an admin Command Prompt, and run this command:

   reg delete "HKLM\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\{37EA5771-3352-4A52-9FAC-9297331DAEBD}" /f

   Press Enter.

10. Restart Windows.

That’s it. Remote Desktop Services should now start correctly.

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Option 2: Fix the ServiceDLL registry entry manually

1. Open Regedit.exe and go to:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TermService\Parameters

2. Double-click ServiceDll
3. Set its data to %SystemRoot%\System32\termsrv.dll
   (Also, ensure that the value type is REG_EXPAND_SZ instead of REG_SZ.)
4. Exit the Registry Editor.

Check if termsrv.dll exists

Additionally, make sure that the module termsrv.dll exists in the C:\Windows\System32 directory.

You may check the integrity of the file by running the following command from an elevated Command Prompt:

sfc /scanfile=C:\Windows\System32\termsrv.dll

If the above file is missing and Sfc cannot repair it, run the Dism command. Alternatively, you can restore the missing file from WinBIndex.

One of the above steps should take care of the issue.