[TauTau]

This just happened to me: been to North Shroud, and noticed map was set to none. When I entered area, I got the memory message. I have quite some meshes missing from the drop down, including North Shroud, though it is in the Navigation folder. When I reload the bot, I get a message about "no default Navmesh for this map" and it initializes an empty one. I restarted game and bot, still couldn't load that map.
I then copied over that map from live, and it loaded. Maybe that helps