thanks for your reply, I think you are right, there must be something in the main exe which is not released properly, though I try to put a return at the very first line of the init.prg and in this case i could overwrite the program without closing the "main exe".
More Over i release all the private variables and also the null variable which refers to the form called in the init.prg, before returning to the main program and the memory status appears free of any reference to my application. Though there still something which prevent me from overwriting the program.
Anyway it's not that important... if I had to update my application I would close the main program :-)
Thank you very much
Alessio