Didn't work. In Windows/rescache there was a ResCache.mni file and three folders: rc0000, rc0001 and _merged. I took ownership of the numbered folders, deleted them, rebooted the system, and the edited dll had no effect to hide the CommandBar. It was not possible to delete the _merged because no form of ownership was successful. Anyway, this is already too complicated to risk changes without back in the system. Thanks for the help of all of you, Anixx, dhjohns and especially Tihiy for the excellent ONE, which helps us greatly to optimize the traditionaly ugly and useless space of Microsoft's bars.