Software⏱️ 4 min read📅 2026-06-04

How to Fix 0x80040154 Error – How to solve COM Exception Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))?

COM Exception Class not registered error occurs when a COM class is not properly installed or registered on the system.

Quick Answer: Register the COM class using the Windows Registry Editor (regsvr32.exe) or by reinstalling the application that uses the COM class.

📋 Table of Contents

  1. 🛑 Root Causes of the Error
  2. ✅ Best Solutions to Fix It
  3. 💡 Conclusion

The COM Exception Class not registered error occurs when you try to create an instance of a COM class, resulting in an exception with the HRESULT code 0x80040154 (REGDB_E_CLASSNOTREG). This issue affects users who are trying to use COM components in their applications or scripts.

This error can be frustrating as it prevents the user from completing their tasks, and it may also indicate a problem with the installation or configuration of the affected COM class. In this guide, we will walk you through the steps to resolve this issue.

🛑 Root Causes of the Error

  • The primary reason for this error is that the COM class is not properly registered on the system. When a COM component is installed, it needs to be registered with the system so that it can be used by other applications. If the registration process fails or is incomplete, the COM class will not be visible to other applications, resulting in the Class not registered error.
  • Another possible reason for this error is that the COM class is missing or corrupted. This can happen if the installation package is damaged or if the COM class is not properly installed on the system.

✅ Best Solutions to Fix It

Registering the COM Class Manually

  1. Step 1: Open the Registry Editor by typing 'regedit' in the Run dialog box (Windows key + R). Navigate to the following key: HKEY_CLASSES_ROOT\\
  2. Step 2: Find the class ID of the COM class that is causing the error. This can be done by using the 'HKCR' key and searching for the class ID.
  3. Step 3: Right-click on the class ID and select 'Modify'. In the 'Value Data' field, enter the path to the DLL file that contains the COM class implementation.
  4. Step 4: Click 'OK' to save the changes. Repeat this process for each COM class that is causing errors.

Using the System File Checker (SFC) Tool

  1. Step 1: Open the Command Prompt as an administrator. You can do this by right-clicking on the Start button and selecting 'Command Prompt (Admin)'.
  2. Step 2: Type the following command: sfc /scannow. This will scan all system files, including COM class files, for corruption or damage.
  3. Step 3: Wait for the scan to complete. If any corrupted files are found, they will be replaced with healthy copies from a trusted location.
  4. Step 4: Restart your system and try running your application again. The COM class should now be registered correctly.

💡 Conclusion

To resolve the COM Exception Class not registered error, you can follow one of two methods: registering the COM class manually or using the System File Checker (SFC) tool. By following these steps, you should be able to register the COM class and complete your tasks without any issues.

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