To resolve the "Class not registered" error in Windows 10, you should first run the application as an administrator to troubleshoot permission issues; 1. Right-click the application and select "Run as administrator", and set permanent administrator mode in the properties; 2. If the problem DLL is known, re-register with regsvr32 through the administrator command prompt, such as regsvr32 urlmon.dll, uninstall regsvr32 /u if necessary and then register; 3. Repair or reinstall related software, especially Office or legacy programs, use official tools such as SaRA; 4. Run sfc /scannow and DISM /Online /Cleanup-Image /RestoreHealth to repair system files; 5. Ensure that 32-bit and 64-bit compatibility, 32-bit DLLs need to be registered using C:\Windows\SysWOW64\regsvr32.exe; 6. If the problems are common, you can create batch files to register common system DLLs in batches; 7. View the application logs in the event viewer, determine the missing components based on CLSID search and deal with them in a targeted manner; in the end, you need to note that some components are deprecated or are restricted by antivirus software and group policies. You should gradually go from simple to in-depth investigation, and most cases can be solved by re-registration or repairing the software.

The "Class not registered" error in Windows 10 usually appears when an application tries to access a COM (Component Object Model) component that isn't properly registered in the system. This commonly happens with older software, Office applications, web browsers using ActiveX, or tools relying on specific DLLs. Here's how to fix it effectively.

1. Run the Application as Administrator

Sometimes, the error occurs due to insufficient permissions.

• Right-click the application or shortcut.
• Select "Run as administrator" .
• If it works, consider permanently setting it to always run as admin:
  • Right-click the app → Properties → Shortcut tab → Advanced → Check "Run as administrator" .

This doesn't fix registration issues but can bypass permission-related access problems.

2. Re-register the Problematic COM Component

If you know which DLL or OCX file is causing the issue (often mentioned in error logs), re-register it using regsvr32 .

Steps:

1. Press Win X → Command Prompt (Admin) or Windows Terminal (Admin) .
2. Type the following command (replace filename.dll with the actual file):

 regsvr32 filename.dll

Example for common cases:

 regsvr32 urlmon.dll
regsvr32 mshtml.dll
regsvr32 shdocvw.dll
regsvr32 browser.dll
regsvr32 msxml3.dll

? If you get “DLLRegisterServer failed,” the file might be missing or corrupted.

To unregister first, then re-register:

 regsvr32 /u filename.dll
regsvr32 filename.dll

3. Repair or Reinstall the Affected Software

The missing class might belong to a specific program (eg, Microsoft Office, a legacy app).

• Go to Settings → Apps → Apps & features .
• Find the problematic software → Modify or Repair (if available).
• If repair fails, uninstall and reinstall the software.

For Microsoft Office: Use the Microsoft Support and Recovery Assistant (SaRA) or download the installer from office.com .

4. Run System File Checker (SFC) and DISM

Corrupted system files can cause COM registration issues.

Run SFC:

 sfc /scannow

Wait for completion. If issues are found and fixed, restart your PC.

Then run DISM:

 DISM /Online /Cleanup-Image /RestoreHealth

Restart after both complete.

5. Check 32-bit vs 64-bit Compatibility

COM components are architecture-specific. A 32-bit app may fail on 64-bit Windows if the class is only registered in the wrong context.

• 32-bit DLLs are registered under:
  HKEY_CLASSES_ROOT\WOW6432Node\CLSID\...
• 64-bit DLLs use:
  HKEY_CLASSES_ROOT\CLSID\...

Fix:

• Use the correct version of regsvr32 :
  • 32-bit : C:\Windows\SysWOW64\regsvr32.exe
  • 64-bit : C:\Windows\System32\regsvr32.exe

So to register a 32-bit DLL on 64-bit Windows:

 C:\Windows\SysWOW64\regsvr32.exe filename.dll

6. Re-register All Standard System DLLs (Last Resort)

If multiple apps are failing, batch-re-register common system components.

1. Open Notepad and paste the following:

 regsvr32 /s urlmon.dll
regsvr32 /s mshtml.dll
regsvr32 /s shdocvw.dll
regsvr32 /s browserui.dll
regsvr32 /s msxml3.dll
regsvr32 /s atl.dll
regsvr32 /s actxprxy.dll
regsvr32 /s dispex.dll
regsvr32 /s scrobj.dll
regsvr32 /s scrrun.dll
regsvr32 /s vbscript.dll
regsvr32 /s jscript.dll

2. Save as fix_com.bat , right-click → Run as administrator .

The /s flag suppresses success messages. This may take a minute.

7. Check Event Viewer for Clues

If the error persists:

• Open Event Viewer (eventvwr.msc).
• Go to Windows Logs → Application .
• Look for Error entries related to the app or COM .
• Note the CLSID (a GUID like {ABC123...} ).
• Search online using that CLSID to identify the missing component.

Final Notes

• Some COM components are deprecated (eg, certain ActiveX controls). Modern alternatives may be required.
• Antivirus software can interfere with registration—temporarily disable it if needed.
• On managed systems (work/school), contact IT—some registry edits may be restricted.

Basically, "Class not registered" is fixed in most cases by re-registering the right component or repairing the software. Start simple (run as admin, repair install), then move to deeper fixes if needed.

The above is the detailed content of How to fix 'Class not registered' error in Windows 10. For more information, please follow other related articles on the PHP Chinese website!