You can check to see when each user last connected to the Mobility Connector. For instructions, see Auditing User Synchronization Activity
in User Management
in the Mobility Pack Administration Guide.
If a user has not connected to the Mobility Connector for 30 days, the nightly maintenance process automatically removes the inactive mobile device from your Synchronizer system. For more information, see Section 2.14.2, Configuring Automatic Nightly Maintenance.