When there are multiple MID Server "JAR File" (ecc_agent_jar) records with the same file name attached, the MID Server can be stuck in a 30 minute restart loop.

The startup sequencer will run JAR file sync, and compare the file on the MID Server disk with the date in the non-matching record in the instance, and then re-download the same jar from the matching record, so that after restart nothing has changed and we repeat.

One scenario where this happens is if CyberArkIT test creates a new jar file for synch, when you already have an existing jar.

Create two JAR file records for the same filename. e.g. JavaPasswordSDK.jav
Start up a mid server.
It restarts endlessly with the following clues in the agent logs:

On MID Server startup:

06/19/19 11:08:15 (404) File sync worker: ecc_agent_jar Downloading D:\Mid_Server\agent\extlib\JavaPasswordSDK.jar from https://<instance_name>.service-now.com/sys_attachment.do?sys_id=04d6dbf96f374300c015f46abb3ee420
06/19/19 11:08:15 (748) File sync worker: ecc_agent_jar WARNING *** WARNING *** Could not complete file synchronization: 0
06/19/19 11:08:15 (748) File sync worker: ecc_agent_jar Finishing file synchronization: ecc_agent_jar
06/19/19 11:08:15 (748) File sync worker: ecc_agent_jar Setting countdown to 1800 seconds in com.service_now.mid.filesync.JarSyncer

30 minutes later:

06/19/19 06:01:34 (125) FileSyncer.1 Setting countdown to 150 seconds in com.service_now.mid.filesync.JarSyncer
06/19/19 06:01:35 (125) File sync worker: ecc_agent_jar Starting file synchronization: ecc_agent_jar
06/19/19 06:01:35 (297) File sync worker: ecc_agent_jar Deleting D:\Mid_Server\agent\extlib\JavaPasswordSDK.jar
06/19/19 06:01:35 (297) File sync worker: ecc_agent_jar Finishing file synchronization: ecc_agent_jar
06/19/19 06:01:36 (297) Wrapper-Restarter Running under Java version: 1.8.0_152, java PID: 2384, args: stop
06/19/19 06:01:36 (297) Wrapper-Restarter Stopping MID server

And then begin the startup again, and again...

After carefully considering the severity and frequency of this problem, and risk of attempting a fix, it has been decided to not address this issue in any current or future releases. We do not make these decisions lightly, and we apologize for any inconvenience. If you have any questions regarding this problem, contact ServiceNow Technical Support.

Possible Workarounds.

1. Deactivate the original JAR File record, keeping only the most recent active.
2. If both JAR files are required, then rename one of them.