You need TWO files. The first program, this kind of program is usually called a loader, will include the updater.prg, and will call the main.exe after it has checked if any updates are necessary.

>Most of steps are finished & checked... however, I fired main.exe, there are needs for updating files, then updater.prg fired up. However, when it is a need to replace main.exe, error generated...
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>I think the problem is updater.prg fired by main.prg which is included into main.exe, therefore, main.exe is not released from memory... How can I prevent to happen