There was a problem with the latest QuArK not being able to work in Half Life 2 mode anymore. This problem has been fixed!
Another nice new feature is that you DO NOT need to have Steam running while using QuArK!
Only if you wish to build your map and see it in Half-Life 2 or Counter Strike.
AND by simply building your map with the "GO!" or "QuickGo!" command, it will start Steam automatically.
Download the QuArK6.5.0_Beta_1_H-L2_Fix file and read the readme for more information.