In new workspace....

1) Import Model from JDBC (connector is created and bound to source)
2) Preview table and see data
3) Select new connector in Connectors View and "Export Connector" to file system
4) Import that same connector back into Designer
5) Results in deleted jar
6) Preview fails

This is because when replacing a connector (overwriting) we first "Delete" the connector and auto-delete unused connector jars. In this case the "Importer" indicated the jar already existed and would not be imported. But it was too late, the next step in the process deleted the jar that was supposed to remain.

Fix is to change our philosophy and NOT auto-delete jars when they are NOT used.