Hi Matt, thanks for your response! I've continued playing with the updater in the meantime and tracked the problem further. The updater behaves exactly in the way you describe in your mail when it is run not from within the batch files but by simply doubleclicking the updater executable. The update is installed properly. When it is started by the batch scripts, however, the main application starts up before the updater is finished and the latter stops working. When I prevent the main program from starting successfully (e.g. by deleting the ifeffit dll) the updater works fine. Maybe there is a file access problem once the dll is used by athena, gifeffit, etc. ? Peter -- -------------------------------------------------------------- Peter Pfalzer Universitaet Augsburg Tel: +49-821-598-3215 Lehrstuhl fuer Experimentalphysik II Fax: +49-821-598-3411 Universitaetsstr. 1 D-86135 Augsburg Germany Peter.Pfalzer@physik.uni-augsburg.de --------------------------------------------------------------