User “%1” cannot synchronize their mobile device with their mailbox because Exchange ActiveSync has been disabled for this user.

This Warning event indicates that the user specified in the event description is trying to synchronize a mobile device. But that user has not been enabled for Exchange ActiveSync.

To resolve this warning, consider the following:

• If this user has not been approved for Exchange ActiveSync, no user action is required. If you can do this, contact the user and let them know that they will not be enabled for Exchange ActiveSync.

• If this user has been approved as an ActiveSync user, enable that user for Active Sync. For more information, see How to Enable or Disable Exchange ActiveSync for a Mailbox User in the Microsoft® Exchange Server 2007 Help file.

If you are not already doing so, consider running the tools that Microsoft Exchange offers to help administrators analyze and troubleshoot their Exchange environment. These tools can help you make sure that your configuration is in line with Microsoft best practices. They can also help you identify and resolve performance issues, improve mail flow, and better manage disaster recovery scenarios. Go to the Toolbox node of the Exchange Management Console to run these tools now. For more information about these tools, see Toolbox in the Exchange Server 2007 Help.