I have an IDL code to read a set of data files and after some processing I save 4 NetCDF files for each one of the original data files. This code works perfectly on Windows PC, but on Mac the memory runs out and IDL crashes. I tried to improve using temporary and delvar but it does not help on Mac. Then I run this code in a Windows PC and it worked as I reported above. It seems that every time I save these NCDF files the used memory are not released after the IDL procedure appointed to do that finish its task. I tested it on IDL 8.0, and 8.2 in Mac 10.7.5 (Lion). The Windows PC that I mentioned has XP and IDL 8.0. Both computers have 4GB RAM memory (Processor in Mac is i7 and Core2Duo for Windows). I appreciate your feedback for overcoming this situation. Regards, Henry