Outlook 2016 Search Glitch in 2025: How to Fix It with a Registry Tweak

Despite being widely regarded as legacy software, Microsoft Outlook 2016 remains in use by many organizations and individual users in 2025. However, the long-lived email client has recently been plagued by a significant search functionality glitch that has caused frustration among its users. Fortunately, a fix involving a registry tweak has been identified to restore search capabilities, providing a practical solution until Microsoft addresses the issue more formally.

The Problem: Outlook 2016 Search Not Working

The core of the problem lies in Outlook 2016's search feature, which depends centrally on Windows Desktop Search indexing. When this feature breaks, users are unable to efficiently find emails, contacts, appointments, and other data, severely hindering productivity.

Reports indicate that the glitch often follows installation of certain software components or updates that modify registry keys affecting Windows Search’s ability to index Outlook data. Notably, users of Outlook 2016 with integration to Exchange Server environments or those who installed the Google Apps Sync plugin have encountered this issue. The problem manifests as search returning no results or Outlook not indexing new emails, despite their presence in mailboxes.

Root Cause: Registry Key Modifications

A key insight into the cause of the search failure is the modification of the registry key named INLINECODE0 . This key, when set to INLINECODE1 or any non-zero value, disables Windows Search indexing for Outlook data, effectively breaking search functionality in the client.

Several third-party tools and plugins, including Google Apps Sync, are known to alter this registry key, often disabling indexing to avoid conflicts, but inadvertently causing Outlook search to fail altogether.

The Registry Tweak Fix

The practical fix involves manually resetting the INLINECODE2 registry key to enable indexing again. Users can perform the following steps to resolve the search functionality:

  1. Open the Registry Editor by pressing INLINECODE3 , typing INLINECODE4 , and hitting Enter.
  2. Navigate to the following path:

``INLINECODE5 `INLINECODE6 PreventIndexingOutlookINLINECODE7 1INLINECODE8 ModifyINLINECODE9 0INLINECODE10 0INLINECODE11 PreventIndexingOutlook` key offers a reliable immediate fix restoring search functionality. Users and IT professionals should consider this solution as part of their troubleshooting toolkit, while planning for longer-term migration or update strategies to avoid recurring issues.