After a reboot of both the primary hub and UMP robot, the UMP USM portlet fails to load and we see the following error before the USM portlet enters a loading state which never finishes:
An unknown error has occurred.
Refreshing your browser may resolve the issue.
Details: com.firehunter.ump.exceptions.DataFactoryException : com.firehunter.ump.exceptions.DataFactoryException: Column 'CM_CONFIG_ITEM_TO_MASTER.master_id' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. Please check the log for more information.
The disk on the UIM Primary hub where the UIM Server was installed had ~300M free.
In this case, the disk space was consumed by files in the debug directory of the 8.65HF1 version of the spectrumgtw probe.
Freed up ~18G of disk space by deleting the debug directory of the spectrumgtw probe, upgrading the spectrumgtw probe to 8.65HF2, then restarting the primary hub followed by restarting the UMP robot.