[Update] Blizzard has fixed the looping issue. However Battle.net is still down for maintenance due to the ladder reset.

Blizzard is currently having an issue with getting the patch released. When the patch finishes, it starts up downloading again.

Thread describing it is here.

Just hold on and wait for an update. You can still go into your StarCraft II folder and use the Map Editor once you’ve downloaded the patch at least once.

One pretty cool thing to mention is that you can import old maps into the editor. I’m not sure yet if it does Terrain and Triggers or just Terrain.

Here’s a cool video showing just one of the things you can do with the editor.