How to troubleshoot ActiveSync 4.0 or later error codes and messages


This article contains information about how to use Microsoft ActiveSync to connect to a device for the first time and about how to synchronize data. The article describes how to solve many problems that can occur when you use ActiveSync.

  • Many problems with ActiveSync can be solved by switching your device from Remote NDIS (RNDIS) to Serial over USB as its communication protocol. For more information about how to switch RNDIS to Serial over USB, click the following article number to view the article in the Microsoft Knowledge Base:

    938323 You cannot synchronize a Windows Mobile-based device by using ActiveSync 4.x

  • ActiveSync will not install on Windows Vista. Microsoft Windows Mobile Device Center is a new application that you can use together with Windows Vista to perform all the functions of ActiveSync. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

    931937 Description of Windows Mobile Device Center

  • For more information about synchronizing a device with Exchange Server 2003, click the following article number to view the article in the Microsoft Knowledge Base:

    836024 TechNet Support WebCast: Troubleshooting Microsoft Exchange Server 2003 ActiveSync issues

ActiveSync installation

During installation, ActiveSync performs the following tasks:
  • Copies necessary files
  • Registers DLLs that are required for synchronizing data
  • Adds exceptions to Windows Firewall
  • Installs .inf files that are required to link Windows Mobile devices to RNDIS
  • Applies hotfixes that are required for installation
  • During the installation of ActiveSync 4.1 on Microsoft Windows 2000, RNDIS and Windows Media Player hotfixes are installed together with the RNDIS drivers.
  • Restart your computer if ActiveSync Setup prompts you to restart.

Installation issues

In some screens of ActiveSync Setup, "ActiveSync 4.0" is displayed instead of the correct version.

The following conditions can lead to connectivity issues:
  • If you ignore the prompt from the ActiveSync Setup to restart the computer.
  • If you upgrade from Windows 2000 to Windows XP or to Windows Server 2003, you must reinstall ActiveSync.
  • If you upgrade from Windows XP SP1 to Windows XP SP2, you must add the Windows Firewall exceptions that are needed by ActiveSync.
  • If you upgrade from Windows Media Player from version 9 to version 10, you must perform a repair installation of ActiveSync. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

    911421 You may not be able to synchronize digital media to a Windows Mobile-based device after you upgrade to Windows Media Player 10

Symptoms of driver installation errors

If problems occurred when ActiveSync Setup installed drivers, the following symptoms can occur:
  • No USB sound or notification when you cradle your device.
  • The Found New Hardware Wizard prompts you to find driver files on the desktop of your computer.
  • The "USB Device Not Recognized" notification appears in the notification area.
These symptoms might appear if drivers were installed incorrectly. Use Device Manager to verify that drivers are installed for the RNDIS Network Adapter. To open Device Manager, click Start, click Run, type devmgmt.msc, and then click OK.

Common driver installation problems and solutions

  • If ActiveSync Setup prompted you to restart your computer, and you chose not to restart, drivers may not have been installed correctly. Restarting your computer may solve any driver problem that you are experiencing.
  • There might be a problem with the physical connection between your hardware device and your computer. Try the following solutions:
    • If it is possible, bypass hubs or docking stations.
    • Try to connect the device to your computer by using different ports.
    • Try to connect the device to your computer by using a different cable.
  • There might be a problem with invalid desktop drivers.
    • Update the drivers by using Device Manager. To open Device Manager, click Start, click Run, type devmgmt.msc, and then click OK.
  • There might be a bad device state.
    • Restart or "hard" restart your device. If you have encrypted data on a storage card that you are using in the device, refer to the following article before you restart or you perform a hard restart. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

      944102 How to prevent data loss on encrypted storage cards that are used in Windows Mobile devices

  • Hardware issue
    • Contact customer support for the manufacturer (OEM) of your device, or contact the mobile operator for support for your mobile service.

The device works as a network interface

When ActiveSync and your Windows Mobile device use USB over RNDIS to communicate with your desktop, your device is recognized as a network interface. If the ActiveSync icon is spinning, the IP network has been successfully established.

If problems occur during the networking stage of the ActiveSync installation, you will typically see one of two indications:
  • The RNDIS adapter shows “Limited/No Connectivity,” or “Acquiring Network Address” is displayed in the notification area.
  • The RNDIS adapter is present, but the ActiveSync icon in the notification area remains shaded.

Common IP network problems and solutions

  • If the “Acquiring Network Address” notification is displayed, the DHCP Client Service must be started, and its startup type must be set to Automatic. For information about how to configure the DCHP Client Service for ActiveSync, visit the following Microsoft Web site
  • If the RNDIS adapter appears to load correctly, but the ActiveSync icon remains shaded, either the RNDIS bindings are set incorrectly, or ActiveSync is not configured to allow for USB connections.
    • If RNDIS adapter bindings are set incorrectly:
      • ActiveSync sets these bindings during installation. Some VPN clients may override the settings.
      • Configure the ActiveSync network interface to use Internet Protocol (TCP/IP).
      • Optional properties for the ActiveSync network interface:
        • Client for Microsoft Networks
        • File and Printer Sharing for Microsoft Networks
      • No other network interface properties should be enabled. If any other properties are enabled, you may have older ActiveSync drivers installed. If your computer is in a corporate environment, contact the network administrator before you disable any of the other settings.
    • If ActiveSync is not set to allow for USB connections:
      • In ActiveSync on the computer, on the File menu, click Connection Settings, and then click to select the Allow USB connections check box.
  • If your device is in a bad state:
    • Restart the device.

Common VPN problems and solutions

After the IP network connection for ActiveSync is established, the following VPN problems and solutions can be addressed:
  • Some VPN policies do not allow for split-tunneling. Split-tunneling is a networking configuration where your computer is connected to both your LAN network and to the network that is created by the RNDIS connection of the ActiveSync device. An indication that a VPN policy is causing this problem is if your VPN connection or your ActiveSync connection stops working when your device is connected.
  • The VPN policy does not allow for modifications to the routing table. An indication that a VPN policy is causing this problem is if your VPN connection or your ActiveSync connection stops working when your device is connected.
  • The VPN configuration routes all traffic to the VPN server. If this configuration is causing a problem, ActiveSync displays the "Connecting…” notification message and does not show the "Connected" message
    • To determine whether your VPN configuration is routing all traffic to the VPN server, examine the routing tables output by using the route print command. In the output of the route print command there is a Metric column in the Active Routes table. A lower Metric value indicates a preferred route. VPNs will frequently insert themselves into the routing table for each network destination with a metric value of 1.

Successful ActiveSync connections

During a successful ActiveSync connection, the desktop connects to the device by sending an acknowledgement packet to the device over UDP port 5679. After you receive the UDP packet, the device connects with the desktop on TCP port 990. During this process, the ActiveSync icon spins, and the ActiveSync "Connected" notification is displayed. If this process is successful, you will hear the connection sound, and the ActiveSync icon changes to green. If there are problems, the ActiveSync icon continues to spin and does not display the "Connected" notification. If the ActiveSync connection is dropped, the ActiveSync icon returns to shaded.

Common ActiveSync connection problems and solutions

Most connection problems are related to Firewalls or to VPNs.
  • If third-party Firewalls are installed, unblock the ports that are used by ActiveSync. If you do not know how to unblock the ports, please contact your company's support department or the third-party Firewall vendor.
  • Verify that the Windows Firewall configuration is correct and that ActiveSync or Windows Mobile-based device connectivity is listed in the Windows Firewall exceptions.
    • To see Windows Firewall exceptions, click Start, click Run, and then type firewall.cpl.
    • In Windows Vista, click Allow a program through Windows Firewall.
    • In Exceptions, review the programs and the services that are listed.
In Windows XP, the following items are listed as exceptions: ActiveSync Application, ActiveSync Connection Manager, ActiveSync RAPI Manager, and the ActiveSync Service. In Windows Vista, you will see Windows Mobile-based device connectivity that is listed as an exception. If your Windows Firewall does not allow for these exceptions, this can contribute to a connection problem.

ActiveSync files and ports that are used for connectivity

The following ActiveSync files are used during connecting:
  • Wcesmgr.exe
  • Wcescomm.exe
  • Rapimgr.exe
These applications are located in the ActiveSync installation folder. For example, the files may be located in the following location:
C:\Program Files\Microsoft ActiveSync
The inbound and outbound ports that are used by ActiveSync are as follows:
  • Inbound TCP
    • 990
    • 999
    • 5678
    • 5721
    • 26675
  • Outbound UDP
    • 5679

Other connection problems

Connections problems can also be caused by networking applications that modify data on the RNDIS adapter or by device hardware issues.
  • Networking applications that modify data on the RNDIS adapter
    • Most issues with networking applications were fixed with ActiveSync 4.1. Make sure that you are using the latest version of ActiveSync. For the latest version of ActiveSync, visit this Microsoft Web site:
    • You can also disable or uninstall networking applications. Before you disable or uninstall networking applications, contact your company's support department.
  • Device and hardware issues
    • Confirm that ActiveSync on your device is configured to allow for USB connections. In ActiveSync on your device, click Menu, click Connections, and then click to select the Synchronize all PCs using this connection check box


Windows Mobile 5 devices use a common engine for both desktop and Exchange Server synchronization. The items that are synchronized include e-mail, calendar, contacts, and tasks. The items that are not synchronized include notes, files, favorites, and third-party items. When you diagnose an error, determine whether you are synchronizing to your desktop or to an Exchange Server. The error codes are the same if you are synchronizing to your desktop or to an Exchange Server. Troubleshooting varies depending on the synchronization source.

Common error codes

The following error code explanations address common causes. An error code might be the result of a different cause.
  • 0x850020xx
    • Cause: synchronization requires user interaction.
  • 0x850100xx and 0x8600xxxx
    • Cause: Server/Desktop internal error.
    • Solution: If synchronization was recently successful, there may be an error that occurs with the ActiveSync partnership. Delete and then re-create the partnership on the device and desktop.
  • 0x850200xx and 0x80072Exx
    • Cause: Network/radio issues.
    • Solution: Adjust radio coverage. Turn the device's radio off, and then turn it back on.
  • 0x80072Fxx
    • Cause: Certificate (SSL) problems.
    • Solution: Renew the certificate. For information about how to renew certificates, search for "certificates" in Help.

How to troubleshoot desktop synchronization

Error 0x85010017

ActiveSync may not synchronize data with Microsoft Outlook, and this may result in synchronization error 0x85010017. This error might be caused by the presence of a large volume of items in the first synchronization. Or, the error might result from specific large items, such as calendar items with many meeting attendees.

Some specific causes of this error have been resolved in ActiveSync 4.5. If you are using Windows 2000 or Windows XP SP1, upgrade to ActiveSync 4.5. Or, you can archive your inbox to reduce the number of items in the mailbox that are synchronized.

Error 0x85010014

ActiveSync reports error 85010014 because synchronization failed for one of the following reasons:
  • Application data folder is redirected
    • If your application data folder (This folder is under your Documents and Settings folder) is redirected to an external source, you will experience synchronization failures. Please upgrade to ActiveSync 4.5 if you are experiencing this issue.
  • Outlook is in offline mode
    • You may experience synchronization failures if you are synchronizing when Microsoft Outlook is in Offline mode or if Outlook cannot connect to the Microsoft Exchange Server. Please upgrade to ActiveSync 4.5 if you are experiencing these issues. We recommend that you have Microsoft Outlook in the Online mode when you are synchronizing with your device.
  • Outlook script blocking
    • Certain security applications can block the Outlook scripting that is required for ActiveSync to synchronize data with Outlook. Make sure that script blocking for Outlook is not enabled. Look in your security application documentation for information about how to disable script blocking for Microsoft Outlook.
  • Device synchronization application stops responding, or synchronization fails
    • Synchronizing certain data items with a device can cause properties to be set incorrectly. If your device frequently stops responding, or synchronization failures frequently occur, please upgrade to ActiveSync 4.5.
  • Outlook has to be reinstalled or repaired
    • If Microsoft Outlook is not the primary e-mail client on the computer, you might see the following symptoms:
      • Synchronization error 85010014.
      • An error message that states that Outlook is not installed, even though it is installed.
    Upgrade to ActiveSync 4.5 if you are experiencing these issues.
  • ActiveSync is registered incorrectly with Outlook
    • Please see the “Outlook has to be reinstalled or repaired” section in this list more information.

Contact Support

If the ActiveSync problem is not resolved, unfortunately, this content is unable to help you any further. So, you might want to ask someone for help, or you might want to visit the following Microsoft Web site to contact support:
For more information about ActiveSync errors, click the following article numbers to view the articles in the Microsoft Knowledge Base:

912241 You may receive error 85010014 when you try to synchronize a Windows Mobile-based device with a computer by using ActiveSync 4.1 or ActiveSync 4.0

912242 FIX: Error message when you try to synchronize a Windows Mobile 5.0-based device with a computer: "The server is busy (85010017)"

If the articles that are listed in this section do not help you resolve the problem, or if you experience symptoms that differ from those that are described in this article, search the Microsoft Knowledge Base for more information. To search the Microsoft Knowledge Base, visit the following Microsoft Web site: Then, type the text of the error message that you receive, or type a description of the problem in the search field.