Some applications rely on dynamic link libraries (DLLs) to function properly. If a DLL fails to register during installation—such as StellarEWS.dll from Stellar Repair for Exchange—you may need to manually register it.

This article provides step-by-step instructions for manually registering a DLL using the regasm tool, and also guides you in resolving the related error:
“Failed to create COM instance.”

When to Use This Guide

  • Application throws a "COM instance" error after install.
  • DLL not registered automatically during setup.
  • Manual registration needed for .NET based libraries like StellarEWS.dll.

Steps to Manually Register the DLL

Note: You must have Administrator privileges to perform the following steps.

1. Open Command Prompt as Administrator

  • Click the Start Menu
  • Type CMD in the search bar
  • Right-click Command Prompt
  • Select "Run as Administrator"
rum command

2. Run the Registration Command

Copy and run the command below:

c:\Windows\Microsoft.NET\Framework64\v4.0.30319\regasm  "C:\Program Files\Stellar Repair for Exchange\StellarEWS.dll" /tlb /codebase

If successful, you will see: “Type Library registered successfully.”

Still Getting an Error?

If after registration, you still encounter the following error:

“Failed to create COM instance”

…it likely means the DLL didn’t register properly or the system cannot access it.

Troubleshooting Steps:

  1. Ensure you ran Command Prompt as Administrator
  2. Double-check the file path to the DLL is correct
  3. Re-run the regasm command to ensure it's registered
  4. If on a 32-bit system, use this path instead:

c:\Windows\Microsoft.NET\Framework\v4.0.30319\regasm  "C:\Program Files\Stellar Repair for Exchange\StellarEWS.dll" /tlb /codebase

  1. Restart the application or system if needed

Conclusion

Manual DLL registration is a quick fix when setup fails to register required libraries. The regasm tool from the .NET framework is used to register assemblies like StellarEWS.dll that expose COM components.