Mytopo Watermark

I downloaded some maps from MyTopo at resolution 15.  The maps look fine at resolutions up to 14, but at 15 and higher, certain portions of the map are covered by a white box that takes up 1/4 of the screen and says "mytopo".  This watermark covers up areas on the map that I need to see.  Is there any way to get rid of this?

Thanks.