To download your map again using MyDrive Connect, you must remove all map files stored on your computer so that the map can be offered again by MyDrive Connect.
Tip: There are 2 stages to download a map; the map first downloads to your computer, and then installs on your device. If your device is connected, installation starts immediately after the download is complete.
Larger maps can take several hours to download. Make sure you turn off any power saving settings on your computer. For more tips: Advice for downloading updates
Tip: To save time, you can set MyDrive Connect to download updates automatically even when your device is not connected. You can then install the updates next time you connect your device. To use this feature, go to Settings, open the Downloads tab and select to Schedule the download of updates.