Home Office & Outlook 0x80040154
Error 0x80040154

How to Fix Outlook Error 0x80040154 (Class not Registered)

Fix time: 15 mins Difficulty: Medium 0 views Updated: July 2026

Resolve class registration registry mismatches in Outlook and Office installations.

Symptoms

  • Outlook crashes with error: Class not registered (0x80040154)

Common Causes

  • Corrupted system DLL registrations (e.g. dao360.dll) or 32-bit/64-bit Office mix

Step-by-Step Solutions

Method 1: Re-register DLL Libraries

  1. Open Command Prompt as Administrator.
  2. Run: 
    regsvr32.exe "%CommonProgramFiles%\System\Ole DB\oledb32.dll"

Was this guide helpful?

Frequently Asked Questions

Often yes, performing an Online Repair is the most comprehensive solution.