I found the explanation :
When going from Mac to PC and return, I use an USB key, whre the WAV file transits.

On Mac side I use 'drag and drop' inside DAW. But Logic works in a certain way to import this WAV file,
and Digital Performer needs some disk space to do importation. DP uses some space on the USB key to do it,
but space is limited and importation crashes ... If you copy the WAV file from USB key to Mac Hard drive, and make the
importation from that location, ... it WORKS.

Sorry to request help for this little thing, ... But as I needed the push and hold features of last WIN version,
and not yet in the Mac version ... we encounter these types of problems and we can loose time.