In a map i am making, all of the entities are always 'leaked' and i don't know how to fix it
HELP!

You have to find the leak. There is probably a gap between your walls somewhere. The best thing to do is to load your pointfile from your map tab. It will show you a red line where the leak is, sometimes you just have to delete the wall and remake it, if you cant seem to find the gap.

To load the pointfile, just select 'map' and then 'load pointfile'.

http://developer.valvesoftware.com/wiki/Leak