Apparatus is provided for the safeguarding of data recorded on disk and diskettes by tunnel erase magnetic head assembly which comprise a read/write transducer for magnetically recording data along tracks on said disk and a pair of magnetic erase transducers adjacent to the read/write transducer for limiting the width of the recorded data. The apparatus for safeguarding the recorded data comprises apparatus for sensing the activation of the erase and/or read/write transducer and apparatus responsive to such sensed activation for determining if the activation is erroneous.