While trying to add a partition under monitoring, spectrum is showing 'Threshold cannot be evaluated'. Calculations of disk size shows "invalid value"
 

SNMP agents using integer32 can't process disk partitions higher than 1TB (typically higher than 1.2 TB) . In MIB Tools, the hrStorageSize 1.3.6.1.2.1.25.2.3.1.5 may show a negative value. Spectrum cannot process a negative value.

Spectrum 10.2.3
Windows Host server

This is a vendor issue on the SNMP agent used to gather the partition data. Recommend to contact the vendor in regards to the SNMP agent. 

References: 

Windows: 
https://social.technet.microsoft.com/Forums/windowsserver/en-US/6cccdcab-faa7-456f-9a51-32b9668736a8/disk-too-big-for-snmp?forum=winserverManagement 

NET-SNMP agent: 
https://sourceforge.net/p/net-snmp/bugs/1837/