Those dang cart paths!
Unplayable Official Rules Definition: Rule 24-2: Immovable Obstruction
If your ball comes to rest on or near a cart path and it interferes with your swing or stance, you are entitled to a free drop.
Assess the situation before touching your ball. There may be circumstances when playing off the cart path is a better option.STEP 1: Take your stance to determine full relief. STEP 2: From new ball position, once full relief is established, measure one club length from there, but no nearer to the hole. STEP 3: Stand with arms outreached and parallel to the ground. Drop within the one club length.