I know this is old, but for me this happened because I upgraded a project from 4.24 to 4.6, In your build settings under Android there should be a check box for ‘use gradle instead of ant’ , in 4.6 this box does not exist, so you have to update a variable in defaultengine.ini (just search for gradle) from FALSE to TRUE. Has to do with your target NDK, which is kind of a whole different issue/change between 4.24 and later versions