Symptoms
When navigating to USM, a "broken heart" icon is displayed, and alongside it a yellow triangle.
Hovering over or double-clicking the yellow triangle brings up a warning saying "unable to retrieve Nimsoft Health Monitor Status".
<Please see attached file for image>

Double-clicking on one of the error messages in the above window, or checking the portal.log will reveal the following exception:
Details:?No element found for key description?Stack Trace:?(38) , No element found for key description?at com.nimsoft.nimbus.PDS.getType(PDS.java:1224)?at com.nimsoft.nimbus.PDS.getString(PDS.java:1546)?
Solution
The cause of this defect (and the associated exception) is that somewhere in the environment, there is a probe or probes which do not have the "Description" field populated. You can view this in Infrastructure Manager - click on a robot and look at the list of probes on each robot. You will see a "Description" column - for example, the Description for the controller probe is "Robot process and port controller."?Very likely this is caused by a custom probe (as all official Nimsoft probes should have this field populated) - so I'd start by checking any robots where you have a custom probe running and see if the Description column is blank on any of them.?If so, you have two options:?1. Right-click the probe and select Edit... and change the description in IM?2. Right-click the probe package in the Archive, and select Edit... then change the description in the Package Editor, and then re-deploy the probe to the necessary robot(s).?We will be fixing this in a future release so that we won't require every probe to have a description set - it is not uncommon for custom/field-developed probes to have nothing set for this - but in the meantime if you're able to set the Description for all probes in the environment it would resolve the "unable to retrieve health monitor status" issue.?