Improving error handling when mounted partitions not found

[agent_kith]

Can the error handling be improved so that it tells this dumb user (me!) that the mounted partitions were not found, instead of chasing up on the REST server errors.

Hmm. It depends on the nature of the system operation (blocking vs non-blocking)... If it's a blocking call, and there's a problem, the front end (web client) can only see that the REST server is dead. I'll dig deeper into this when I can and see what's wrong.