MapSource Free Install Without Media
Download MapSource software updater from Garmin. The version as of December 4, 2007 is 6.13.6, and the trick also works on Map Source version 6.13.5.
Unpack or extract the content of MapSource_6136.exe
downloaded using WinRAR.
From the extracted files, run MAIN.msi or MSMAIN.msi.
Then, run Setup.exe.
Note: The sequence to execute Main.msi and then Setup.exe is important to avoid “Previous MapSource not found!” error.
Garmin MapSource now installed.