At times, the File Reader will restart simply because it has not received a heartbeat within the timeout period. Increasing it can reduce the number of File Reader restarts if there are some connectivity problems involved.
Resolution
1. Enter the advanced settings of the server in question.
2. Locate and change the following value:
BoxMonitor.HeartbeatGapBeforeRestart
The heartbeat is expressed in milliseconds. As a good start during troubleshooting, you might double the number.