PROBLEM: There is currently an upper limit to the amount of data that can be contained in an output report due to the 65536 rows constraint for the .xls format. We'll be converting to another format in the future, but for now, if you see a "Working..." wheel spinning for a long time in the upper right-hand corner when attempting to generate an output report or a PowerPoint presentation and you have a relatively complex model with many scenarios, then you've likely exceeded that limit.
WORKING SOLUTION: The best way to work around this is to duplicate the model (multiple times if needed) and essentially divide it into several parts, generating reports for each part separately then combining them together into one file if you need. For example, if Model A is too large, then you can duplicate and divide that into Models B+C which each contain 1/2 of the scenarios from Model A.
DEVELOPMENT SOLUTION: Starboard has not set a resolution date as the Microsoft limit constrains the output. However, the roadmap has several releases that would allow in application presentation of greater amounts of data.