I'm having this issue as well. Probably going to try a full reinstall here in a little bit.
*edit - uh.. nevermind I guess. Third restart and it works.
*another edit! I'm not a big fan of things not working and then working without me knowing what I did, so I restarted again and let everything get going before trying. Apparently bitdefender decided it didn't like enb anymore. I rarely restart - so I might've killed the BD process before for whatever reason, I've only been playing enb again for the last few days, I'm guessing that when it worked earlier I had it launched before the few on-startup programs I run got going. Wouldn't launch with bitdefender running - will launch without. This may be 100% unrelated to everyone elses problems, sorry!