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ActiveSync

Microsoft data synchronization app

Wikipedia contributorsAdapted for Fathomly · View authors
4 min read
Source updated July 17, 2025
Image credit is listed at the end of this article.

ActiveSync is a mobile data synchronization app developed by Microsoft, originally released in 1996. It synchronizes data with handheld devices and desktop computers.

01Overview

ActiveSync allows a mobile device to be synchronized with either a desktop PC or a server running a compatible software product.

On desktops, ActiveSync synchronizes emails, calendar, contacts and tasks with Microsoft Outlook, along with Internet bookmarks and files. ActiveSync does not support all features of Outlook. For instance, contacts grouped into subfolders are not transferred. Only the contacts which are not in a subfolder are synchronized. In case of Exchange Server, only emails, calendar, contacts and tasks may be synchronized.

In the Windows Task Manager, the associated process is called wcescomm.exe.

ActiveSync also provides for the manual transfer of files to a mobile device, along with limited backup functionality, and the ability to install and uninstall mobile device applications.

Supported mobile devices include PDAs or smartphones running Windows Mobile, Windows CE, BlackBerry 10 or iOS but not the older BlackBerry versions, Palm OS and Symbian platforms. Windows Phone 7 doesn't support desktop ActiveSync synchronization.

Starting with Windows Vista, ActiveSync has been replaced with the Windows Mobile Device Center, which is included as part of the operating system.

02Release history

Version Operating systems Release date Major changes
1.0 Windows 95 1996-09-10
  • Initial version (under name H/PC Explorer)
1.1.7077 1997-03-19
  • NT4 support
  • Stability and compatibility fixes
  • Revised EULA
2.0 Fall 1997
  • Renamed to Windows CE Services
  • Support for Windows CE 2
  • Windows CE 1 support dropped
2.1 1998-02
  • Support for Windows CE 2.1x
2.2 1998-09
  • NT4 installation easier
  • 33% faster than 2.1
3.0.0.9204 1999-08-16
  • Renamed to ActiveSync
  • Faster, simplified, and vastly improved.
  • Removed the association between RAS/DUN and the Windows CE connection stack
3.1.9386 1999-11-24
  • USB synchronization and the inclusion of the AvantGo host client
  • Auto-adjusting baud rate
3.1.9439 ?
  • Sync fixes
3.1.9587 2001-07-31
  • Added synchronisation support for Microsoft Exchange Server 2000
  • Fixes for Outlook 98 / 2000 Security updates
  • Fixed a problem with the USB sync option
3.5.1176 2001-08-06
  • Integrated support for new Windows XP and Office XP releases and Pocket PC 2002
  • Improved USB functionality, security and sync performance
  • New connection sounds
3.5.12007 2002-03-01
  • Revised high color program icon
3.6.2148 2002-11
  • Support for the new range of Smartphone devices
  • Customary security updates and synchronisation performance improvements
  • New Get Connected Wizard
  • Improves on remote synchronisation by preventing error messages and dialogues from halting sync process
3.7.3083 2003-05-06
  • Minor updates to internal icon set
  • Corrects a discovered security flaw in ActiveSync
  • Improvements to the synchronisation wizard, other UI changes and general enhancements
  • Improvements to support forthcoming Microsoft Office 2003 release and Windows Mobile 2003
3.7.1.3244 2003-10-10
  • Improvements to USB drivers and issues related to synchronisation
  • Get Connected Wizard's interface modified slightly.
3.7.1.4034 2004-03-26
  • Fixed reported bugs with Windows Explorer and XP Firewall integration.
3.8.0.5004 2005-01-06
  • Secure functionality and provide updates for Windows XP SP2 systems
  • Performance improvements in synchronisation
  • Circumvents XP Firewall prompts that users experienced with other program versions upon first run.
  • Disables the Ethernet (LAN, Bluetooth) and RAS (Modem and WAN) connection method by default
4.0.4343 2005
  • Users able to specify installation directory
  • Removal of on-personal area connectivity options from the synchronisation mix.
  • Services for connections with Microsoft SQL server are included, along with a synchronisation update for Windows Media Player 10
  • GUI refresh
4.0.4358 2005
  • Retail version included only on Windows Mobile 5 device CDs
4.1.0.4841 2005-11-18
  • Critical update
4.2.0.4876 2006-06-06
  • Microsoft Outlook improvements: Resolves issues relating to error code 85010014
  • Proxy/DTPT interaction improvements: Improved auto configuration of device Connection Manager settings when desktop has no proxy path to the Internet
  • Improved Desktop Pass Thru behavior with ISA proxy failures
  • Partnership improvements: Better resolution of multiple devices with the same name syncing with the same desktop
  • Connectivity improvements: Better handling of VPN clients (resolve unbinding of protocols from our RNDIS adapter). New auto detection of connectivity failure with user diagnostic alerts
  • New troubleshooting utility
4.5.5096 2007-02-13
  • Faster file transfer speed and photo sync via Outlook are only available for Windows Mobile 5.0 powered devices.
  • Users of Microsoft Exchange 2003 Service Pack 2 with devices running the Messaging and Security Feature Pack for Windows Mobile 5.0 will benefit from the following feature enhancements included in ActiveSync 4.5: Direct Push Technology, local device wipe, and certificate powered authentication to Microsoft Exchange.
  • Microsoft Office Outlook 2000 not supported
  • Conversion of database files for use on a mobile device is not supported
  • Conversion of font files for use on a mobile device is not supported by ActiveSync 4.5
Watch videos about ActiveSyncExplainers and documentaries on YouTube (opens in a new tab)

Sources and credits

This article is adapted from the Wikipedia article “ActiveSync”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

Images, from Wikimedia Commons:

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Related topics

Handheld PC Explorer

Handheld PC Explorer, or as it is more commonly referred to, H/PC Explorer was the Windows PC host client for the inaugural generation of Microsoft Windows CE 1.0 based embedded PC companion devices, the Handheld PC.

SyncToy

SyncToy was a freeware tool in the PowerToys suite that provided a graphical user interface for synchronizing files and folders in Windows versions XP, Vista, 7 and 10. It was written using Microsoft's .NET Framework and used the Microsoft Sync Framework.

Windows Mobile Device Center

Windows Mobile Device Center is a synchronization software program developed by Microsoft, and the successor to ActiveSync. It is designed to synchronize various content including music, video, contacts, calendar events, web browser favorites, and other files between Windows Mobile devices and the Microsoft Windows operating system.