Nuvi 3597 with SD Card

Hello Everybody,

On my Nuvi main memory I have 3 maps: 1. CN North American NT 2020.20 US & Canada 2. Cnna - Na - Dem North America DEM 3. CN North American NT 2020.20 Basic 3D - US & Canada

I have a lifetime subscription for the US Maps. The Nuvi came with US as I bought this in the US.

Apart from this I do have other maps for Europe and Middle East for which I have a lifetime subscription. I also have an OSM Map for India.

With the US Maps JAVaWa says that there is an error and that the redraws etc will not be fast. I have also found that at times my Nuvi simply goes crazy and decides to freeze up or not work at all, especially in the US. I go to Setting MyMaps to choose which map I wish to use depending on the country I am in. How do I go about ensuring that the gmapprom.img is the only one that I need and not the duplicates which I do not understand how they are installed with Garmin Express.

Any suggestions? Thanks for the expert advice. Jay