If you are using Win8.1 with WB please do not install the optional update in the list until after you upgrade WB to the latest files which will be out on Wednesday. The automatic ones should be fine, just avoid the optional one for now.
Thank you, Neil, for your reply! I updated all 33 updates and the optional KB2955164 update, and received a black screen after entering my PIN. I tried many different fixes, but nothing helped. Thankfully someone said long ago to make sure you have another Admin user account, so I was able to log in to that account and delete that optional update. After that, I was able to log into my regular user account.
I just saw this thread and was going to warn of the optional update. I'm glad to know that it had to do with an incompatibility with WB.
Thanks again!