After the map updates on mid-May, both the HERE Maps and Drive apps for Windows Phone 8 stopped working, even worse, launching them made the phone reboot. The obvious fix would be an hard reset of the phone, but that would mean a lot of work, backing up everything. Here is another way to fix this problem without a reset:
run SysApp Pusher and install Lumia storage check beta from the Nokia tab. You have to install the beta version, not the release one, as the release version misses the feature you will need in the next step
run Lumia storage check beta and select the SD card as the destination of Maps
run HERE Maps: now it is not crashing anymore, but you will have to download the maps again, this time on the SD card
using this method, you will not recover the phone memory occupied by maps that you downloaded previously
