I have big problems to get OnProgress to work. I'm doing a little program for extracting and installing files. I have read the helpfile and looked at the code for Demo1. I don't really get how often the 'ProgressUpdate' updates. I'm also a bit confused about FileSize. Do this variable give you the total size of the file uncompressed , how many bytes or Kb extracted or how much remains to extract? My idea was to have some sort of a progress bar in the program. I would appreciate if someone could help me here. /Stefan