Overwrite repeatability of exchange‐coupled multilayer for light‐intensity‐modulated overwrite (OW) was studied by using Arrhenius analysis. A computer simulation showed that typical OW disks and a conventional nonoverwrite (NOW) disk have similar maximum temperature during recording. Nevertheless, the overwrite repeatability of the OW disks was smaller than that of the NOW disk. The degradation mode characteristic to the OW disks was found to have lower activation energy than the conventional NOW single‐layer disk. The degradation mode was caused by initialization noise resulting from domain‐wall fluctuations under a large initializing field, and was reduced by using a transition‐metal dominant memory layer with high‐domain‐wall coercivity. An overwrite repeatability of more than 106was achieved. ©1995 American Institute of Physics.