Ok, so I made a map in the Galaxy Editor a couple of nights ago, then tested it. It worked just fine. No graphics errors at all and everything ran smooth at highest settings. Today I downloaded a slew of maps to try other peoples creations. Each one I load up will do this same thing: Every time something moves on the screen, it will leave a black mark where it has been. This means if the camera moves, the screen goes black. If only a unit is moving, it will leave a shadow trail of where it has moved. I figured it must be my video settings, so I adjusted everything down to lowest settings, played with resolutions, and even the refresh rate. If I make changes to the graphic settings or if i minimize the game, then bring it back up, the graphics will seem to "refresh" until something moves... creating black splotches again.
As a control experiment to see if something wonky was happening with my graphics card or computer, I re-opened the map I had made 2 nights prior. It worked just fine... no graphical errors at all. Only maps I download seem to be doing this...
EDIT: Oh, and my graphics card drivers are up-to-date. And if it makes any difference, I have an Nvidia GEFORCE GTX 260M @ 1GB
Not sure... I actually don't have a beta key. I'm not using a cracked copy of the game either hahaha... I just downloaded it to play in the editor and was surprised that the test map in SC2 feature worked.
So I don't know what could possibly be going wrong since it is a legit beta. The game works offline, no issues there... it's just the maps I download that seem to have issues.
I've been having a similar problem, it only occurs in third person maps. Most all of the third person shooter maps I've downloaded cause the camera to eventually just go black except for a few flickers of unit textures. I'm using a legitimate beta client and editor.