Software⏱️ 3 min read📅 2026-06-19

How to Fix 0x8007042C Error – Getting error 0x8007042C when updating Outlook Offline Adress Book

Outlook Offline Address Book error 0x8007042C

Quick Answer: Try reinstalling Outlook or running the Office Repair tool to fix the issue.

📋 Table of Contents

  1. 🔍 Why This Happens
  2. ✅ Best Solutions to Fix It
  3. 🎯 Final Words

The error 0x8007042C is a known issue that occurs when the Outlook Offline Address Book (OAB) fails to update. This problem affects users who rely on the OAB for contact information, and it can be frustrating when new contacts are not reflected in their local address book.

In this troubleshooting guide, we will walk you through the steps to resolve the issue and get your OAB updated.

🔍 Why This Happens

  • The first main reason why this error happens is due to a corrupted or missing COM+ Event System service. The Background Intelligent Transfer Service (BITS) relies on this service to update the OAB, but if it fails to start, the BITS service will also fail, resulting in the 0x8007042C error.
  • Another possible cause is a misconfiguration of the Outlook installation or profile settings. If the Outlook file is corrupted or the profile is not properly set up, it can lead to OAB update issues.

✅ Best Solutions to Fix It

Re-registering the COM+ Event System service

  1. Step 1: Step 1: Open the Command Prompt as an administrator and navigate to the folder where the COM+ Event System service is installed (usually C:\Windows\System32).
  2. Step 2: Step 2: Run the following command to re-register the COM+ Event System service: regsvr32 comsystem.dll. This may take a few minutes to complete.
  3. Step 3: Step 3: Restart your Outlook application and try updating the OAB.

Repairing or reinstalling Outlook

  1. Step 1: Step 1: Open the Control Panel and go to Programs and Features (in Windows 10) or Add/Remove Programs (in older versions of Windows).
  2. Step 2: Step 2: Locate the Outlook application and click on it to select it. Then, click on the 'Change' button and select 'Repair'. This will attempt to repair the installation.
  3. Step 3: Step 3: If repairing the installation does not work, try uninstalling and reinstalling Outlook from scratch.

🎯 Final Words

If you have tried both of these methods and are still experiencing issues, it may be necessary to re-image your machine or seek further assistance from a Microsoft support specialist. However, before taking this step, make sure to back up any important data and settings to avoid losing them during the process.

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