COM and .NET errors after Office architecture migration

COM and .NET errors after migrating Office architecture (e.g., from 32-bit to 64-bit or vice versa) typically occur due to compatibility issues. Here’s how to troubleshoot and resolve these problems:

1. Check Office Architecture Compatibility

• Ensure that your application targets the correct architecture (x86, x64, or Any CPU).
• Rebuild your .NET application with the correct platform target in Visual Studio.

2. Repair or Reinstall Office

• Go to Control Panel > Programs and Features.
• Select Microsoft Office and choose Repair.

3. Register COM Components Manually

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

4. Update .NET Framework

• Ensure the latest .NET Framework version is installed and updated through Windows Update.

5. Use Late Binding in .NET

• Consider using late binding in your application to reduce dependency on specific Office versions.

6. Install Required Office Interop Assemblies

• Install the Microsoft.Office.Interop assemblies through NuGet or ensure correct references in your project.

7. Check Registry Entries

• Verify that necessary COM components are registered in the Windows Registry:
  • Check under HKEY_CLASSES_ROOT or HKEY_LOCAL_MACHINE\SOFTWARE\Classes.

8. Consider Microsoft Tools

• Use Microsoft Support and Recovery Assistant (SaRA) for diagnosing Office-related issues.