Since the late series of PD 2.5 and up to present 3.0.4124, whenever I tried to download a mapset of greater than 100-150Mb in size to my eTrex Vista Cx, the VM/Windows XP would crash out without warning halfway through the download. This is when mapset has already been built and is physically uploading the mapset onto the unit. So I am not restricted to uploading a very small mapset ie. A pain. As it always happen somewhere in the upload process, I wondered if there's a USB connectivity issue. I have tried to disconned all other USB devices, closed all Mac programs and nothing seemed to make a difference apart from the size of the mapset. Anyone seen similar? Any suggestions as to what might be the issue? I am using 1st gen MacBook with 2G of RAM. Mac OS X 10.4.9. Windows XP Pro with all the latest updates. Mapsource 6.12.4. That is, all with the latest version software, including firmware on the Vista Cx. BTW, anyone know where Mapsource stores their built mapsets prior to upload? I note that with each crash, my VM's disk space would start to vanish. It's getting serious with multiple attempts to upload 470Mb sized mapset. Thanks in advance.