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"Remove Existing Microsoft ActiveSync" error when attempting to downgrade to Microsoft ActiveSync 3.8


Applies To

  • HPC2000
  • Windows CE .net 4.0, 4.1, 4.2
  • Windows CE 5.0


When attempting to downgrade from Microsoft ActiveSync 4.0 or 4.1 to ActiveSync 3.8, you receive the following error message:

Remove Existing Microsoft ActiveSync
The version of Microsoft ActiveSync installed on this computer is more recent than the one you are trying to install. You must remove the existing version before you can install an earlier version.

To remove a program, use Add/Remove Programs in Control Panel.

At this point the installer will terminate and you will be unable to install the older ActiveSync release. This guide outlines suggested measure you can take to work around this issue.

More Info

Having uninstalled ActiveSync 4.0 or 4.1 from your computer, the ActiveSync 4.x uninstaller has failed to correctly unregister the ActiveSync 4.x software application. Part of an ordinary check during the ActiveSync 3.8 installation routine encounters the remains of ActiveSync 4.x and presents the user with error 43; as outlined in the overview section of this article.

NB: All steps outlined in this article are subject to following CESDS0093 Unable to load ActiveSync 3.8 after uninstalling ActiveSync 4.0 or 4.1 after the removal of ActiveSync 4.x

Step 1:

  1. Reboot your computer with your Handheld PC disconnected
  2. Reistall ActiveSync 4.1
  3. Reboot your computer
  4. Disconnect from the Internet and disable any Anti-Virus software running on your PC
  5. Open the Windows Task Manager, select the Process tab
  6. Highlight the following processes and click End Process:
  7. Uninstall Microsoft ActiveSync 4.1 from Add/Remove Program in the Windows Control Panel
  8. Reboot your computer
  9. Attempt to reinstall ActiveSync 3.8

Step 2:

  1. Navigate in Windows Explorer to:
    C:\Program Files\Microsoft ActiveSync
  2. Delete all the files in this folder, but not the top-level Microsoft ActiveSync directory
  3. Perform a repair install on Microsoft Office 2000/XP/2003 from Add/Remove Programs in the Control Panel
  4. Reboot your computer
  5. Atempt to reinstall ActiveSync 3.8

Step 3:

WARNING: If you use a Registry Editor incorrectly, you may cause serious problems that may require you to hard reset your Handheld PC back to its factory installed configuration. Edit your Windows CE registry at your own risk.
  1. Open the Windows Registry editor
  2. Navigate to:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows CE Services
  3. Locate the String vale named:
  4. Change the value to read 3
  5. Locate the String value names:s
  6. Change the value to read 7
  7. Reboot your computer
  8. Atempt to reinstall ActiveSync 3.8

Step 4:

NB: This action will delete all partnership and software installation settings that you have preconfigured
  1. Open the Windows Registry editor
  2. Navigate to:
  3. Delete the sub keys:
    Windows CE Services
  4. Navigate to:
  5. Delete the sub keys:
    Windows CE Services
  6. Reboot your computer
  7. Atempt to reinstall ActiveSync 3.8