Hi . Many thanks for responding. I use Memory Map 5.2.7 build 890. I believe, although I cannot be sure, that problems started when I updated to the latest build. I now seem to have resolved the situation (using trial and error) by changing the ports. On memory Map set up I am now using Generic(NMEA) with Port COM 7 and Baud 9600. When I go into system GPS settings the GPS program port is also set to COM 7. Are these the settings you are using? Is it just necessary to set both ports at the same setting or does it have to be 7. Many thanks for your interest.