click the apple logo in the upper left corner of the Mac screen and select "system preferences …" from the drop-down menu. In the pop-up settings panel, click "Security and Privacy" on the small house icon in the first line.

% R7 E* n' d' v" m. y Seven Degrees Apple Computer Software

Select the "General" tab in the Security and Privacy Settings panel (in fact, it should be there by default). See the options marked with red boxes in the screenshot above. Just change the downloaded applications from the default "Mac App Store and recognized developers" to "any source".

But the button is grayed out ... If it is locked, click the lock button in the lower left corner to unlock it.