The first place I would check is the digital pocket memo itself.  To do this:
Connect the Philips Digital Pocket Memo, then go to Start > My Computer.  Find the DPM in the ‘Removable Drive’ section and search the contents.
Secondly, I would check the default ‘Backup Location’
If that doesn’t show themissing” audio files.  Make sure that you are logged in under the proper user account.
Finally, do a search for .DSS or .DS2 audio files on your computer.
Verification Source: In-House Testing