There was a thread today on the Analysis Services forum where someone appeared to be having an issue with a data type overflow. Multiple large, positive, integer values were aggregating up to a negative amount. If you are interested the full thread is here: Re- negative values on a measure Basically the database and the DSV were increased to a bigint data type, but the issue was still occurring. What I believe is happening here is that the measure in the cube was set with an int data type. To fix ......