Hammer not starting after DLC update
yup, hammer works again, but trying to rebuild a map in the portal 2 editor in game still does not work.
Hammer works, but I came across a weird issue... I did a re-compile to see if everything worked, and... the videos I put in my elevators are just black screens.. Not sure what that's all about, but I noticed it.
[Released] Power Interference
[Released] Rust and Dust (Spotlight Map!)
[Released] Multiportal
Quote from a valve employee if you're still experiencing problems with hammer:
The issue is that the build tools in SDK were colliding with the tools now packaged into Portal 2. By deleting the files, Portal 2 should put the correct files back on your disk.
I'm glad they fixed it this fast... I was about to be really pissed off.
It isn't fixed yet, at least I don't think so, that's just a loophole Josh found.
Portal 2 updated again, so this might be the fix.
im just gonna uninstal and reinstall EVERYTHING, and see if that works
now thaT there is a fix, i can't even keep my internet up for 5 minutes to download it. 
i can usually fix this problem by restarting (no other way works), but now i've restarted at least 5 times and nothing has worked.
Aperture Science: We do our science asbestos we can!
It seems that everything is working for the most part now. I haven't gone in depth, but it looks like Hammer is working again, and now the in game editor is able to rebuild the maps for testing, though it took a removal of the authoring tools, verifying the game cache, then reinstalling the tools.
AND THUS WE HAVE A FIX TO THIS MADNESS
it was put into the game as well so that if people don't socialize, they can at least have the message in game so that they still get the info.