You haven't given us an awful lot to go on. You say it takes a long time to load - how long is long and how many VIs are you loading. Have you saved front panels with a a lot of data? How are you managing references, array building, string building? Are you using a lot of global/local variables. There any number of improper programming techniques that can cause excessive memory use. Unless you provide more details or attach your program for someone to review, the best advice I can give is to review the shipping document "LabVIEW Performance and Memory Management" and search this forum and NI Zone for memory management topics.