Okay, so I'm kind of in a panic mode right now, and I'm wondering if anybody might have a solution for me. So, within the last two hours, I just showed off some additions to my map to my friend, I closed Hammer and the Source SDK (without saving any files, I didn't want to save my changes), and then we played L4D2 for about an hour. Afterward (within the last half hour), I opened the same file again, and now all of my entities are missing from my map! My objects, doors, lights, triggers... everything just disappeared, and all that's left is my brushwork. Hammer isn't missing any of the actual entity files, as I can instantiate new entities of any kind -- it's only my previously created entities that are missing. ...Is there anything I can do?