There was a some similar problem reported here with OSX/macOS, @rich2005 or/and other members of this forum got some solutions (sorry I don't recall which one)
But while waiting for them (they are in a different time zone), please give your full mac version/specification, and GIMP version, this will help them better to answer you
But while waiting for them (they are in a different time zone), please give your full mac version/specification, and GIMP version, this will help them better to answer you