Technical Tip

Contact Sync Optimization – Eliminating Outlook Performance Issues
Last Updated: January 2026

Overview

Recent Microsoft Outlook and Microsoft 365 changes have introduced background contact updates that can significantly slow contact synchronization. These updates are primarily caused by the Outlook Social Connector (OSC), which may modify contacts even when no meaningful changes have occurred. This behavior leads to unnecessary item updates, extended synchronization times, and increased battery usage on mobile devices.

This document explains the cause of the issue, its impact on contact synchronization, and the recommended configuration changes required to optimize performance.

Root Cause: Outlook Social Connector

Microsoft has been testing and deploying new background contact update mechanisms associated with the Outlook Social Connector. These updates can affect contacts in any mailbox, including shared and resource mailboxes, and may occur even when the contact data has not changed.

Although service accounts are not intended to be affected, real-world environments have shown that service and sync source mailboxes can experience these unnecessary updates.

Public Folder contact sources currently appear to be exempt from this behavior.

Impact on Contact Synchronization

When the Outlook Social Connector is enabled, Outlook may update contact information using data from the Global Address List and other social data sources. Each update causes the contact item to change, which triggers synchronization logic to reprocess the item.

This results in a repeated update cycle often referred to as a “ping-pong” effect. The outcome is excessive processing, long synchronization times, and unnecessary workload on both servers and clients.

In many environments, synchronization that should complete in under a minute can take an hour or longer when the Outlook Social Connector is enabled.

Required Configuration: Disable Outlook Social Connector

To optimize contact synchronization, the Outlook Social Connector must be disabled through policy-based configuration. Disabling the add-in locally is not sufficient.

In Office 365 or Hybrid environments, both cloud-based policies and any existing local Group Policy configurations must be implemented.

Microsoft 365 / Office 365 Configuration

This is the recommended and preferred approach for modern Microsoft 365 environments.

Sign in as a Global Administrator or Tenant Administrator.
Navigate to the Microsoft 365 Apps Admin Center at: https://config.office.com/officeSettings/officePolicies
Create a new policy named “Disable OSC”.

Apply the policy to all users or to a dedicated security group containing at minimum:

Source mailboxes used for synchronization
Any users who open or access those source mailboxes
When configuring policy settings, search for “Social”.
Enable the setting “Turn off Outlook Social Connector”.
Save and activate the policy.

Most organizations choose to apply this policy to all users, as the Outlook Social Connector typically provides minimal benefit and frequently introduces performance issues.

DidItBetter Software Configuration Note

If the Outlook Social Connector cannot be disabled for all users, contact your DidItBetter Software representative to enable the “Ignore Destination Item Changes” option within the synchronization template relationships.

If this document was provided by a DidItBetter Support Engineer and access to the replication server exists, this option may already be enabled.

On-Premises Active Directory Group Policy

For on-premises or hybrid Exchange environments, the Outlook Social Connector should also be disabled using Active Directory Group Policy.
Create the Group Policy "the Microsoft way" for most all configurations. 
Microsoft - Manage the Outlook Social Connector with Group Policy

Microsoft-provided ADM or ADMX templates should be used and applied according to Microsoft best practices. The policy must be applied to:

Mailboxes acting as synchronization sources
Users who access or open those mailboxes

If a local Group Policy exists and the organization uses Office 365 or a Hybrid configuration, both the local and cloud-based policies must be implemented to ensure consistent behavior.

Additional Microsoft Reference

Microsoft documentation on cloud-based policy management for Office applications can be found at:
https://techcommunity.microsoft.com/t5/office-365-blog/the-new-cloud-based-policy-management-service-for-office-365/ba-p/480676

Completion Checklist

Outlook Social Connector disabled via Microsoft 365 policy
Outlook Social Connector disabled via local Group Policy if applicable
Policies applied to all synchronization source mailboxes
Synchronization performance verified after policy application