Sorry about the extreme lack of posts. I hope this tip makes up for it 🙂 So, this morning I load FB 4.6 and it hangs. I tried all the usual suspects and still no luck. I searched online and read the amusing story of Adobe wanting to charge people $250 for a tech support call to fix what appears to be a bug. Clearly a one-trick pony company with Photoshop – they sure can’t make anything else work.
Don’t waste your time or money with DumbDobe. A bit more searching yielded this post and it worked for me without reinstall or any other hassle. I wanted to pass along some props to the original poster and give the fix some attention in case this happens to you.
And Adobe is leading the charge for HTML 5? Yikes! I knew I should have been a lawyer.
The Algorithmist 
Did you try to rename your workspace folder?
Worked for me 😉