I downloaded the MapSource version from what is now called post #12. I extracted the RAR files, placed the .gmap folder in %APPDATA%\GARMIN\Maps on C: drive and unlocked using JetMouse with Checksum Fix. This is how I proceeded with all previous maps without any hassle. However, when now trying to install the full size map on an SD card, MapInstall 4.0.1.0 (patched) hangs at the following screen (tried twice, each time same result):

hungmapinstall

Plenty of space on C: drive from which MapInstall runs. After 5 hours still same screen. What am I doing wrong?