Thanks again, Does seem implementing the startDetached() is the better option ( if i understand correctly) as when the app closes , closing down the started sup processes could be problematic. On a side note: Needing to keep the instance around is also an interesting complexity, if logic serves, The app starts a process (perhaps stored in a QList Or QHash) Maintain the state so when the sup-process terminates i can ether re-use the process or remove the process and create another instance . *with the understanding that if the main app closes all sup-process's will close. Is the logic sound?