A scaffold arrangement (1) comprising a scaffold component (2) and a support unit (3) for releasably supporting the scaffold component in an operative position on a scaffold assembly or building, the support unit (3) comprising a mounting portion for fixedly mounting the support unit to said scaffold assembly, a supporting member for seating a first part of the scaffold component, and a releasable locking member moveable to a locking position for locking the scaffold component to the support unit, the arrangement being such that when the scaffold component (2) is seated on the supporting member in said operative position, and the locking member is in said locking position, the locking member is spaced immediately below a second part of the scaffold component (2) and acts as a back-up supporting member for arresting uncontrolled downward movement of the scaffold component (2) relative to the support unit (3).