When the molecular‐beam epitaxial (MBE) growth of GaAs or (Al,Ga)As is interrupted and the surface is exposed to air for other kinds of processing, a high concentration (>2×1011cm−2) of surface defects tends to form which will show up as highly detrimental interface defects if the MBE growth is subsequently resumed. We show that the surface can be protected by a thin epitaxial layer of InAs, which is highly resistant to many kinds of processing steps, and which can be thermally removed before resumption of growth, leading to an ‘‘invisible’’ restart interface.