First, what version of HyperSizer are you running? For really large models with a lot of load cases, we saw some memory problems with earlier versions of HyperSizer (before 5.
.
Second, one of the things that can cause memory problems is if you have element or nodal "spans" that are very large... by span I mean you have some elements that have IDs that are low and other elements that have IDs that are very high. For example, if you have an element with an ID of 1 and your highest ID element has an ID of 99,000,001, then your span is 99 million... this can cause problems in earlier versions of HyperSizer. The problem is that there are arrays which can span this entire range and Windows 32 bit will not allow the total memory of a program to go past 2 GB of total RAM. Is it possible that your model fits this description?