I have had the same issue for over a year. It started when using Enterprise Gold 23 and continues to be a problem with Enterprise Gold 24. It seems like if I don't open Quickbooks within 24 hrs of closing it, the Passwork Field is grayed out. Many times I will automatically restart my computer before trying to open QB, but sometimes the computer is already locked up. Then, I have to shut off the computer on the tower to close it down because I am not able to go to the "Start" icon to restart. In fact, when it happened this morning, I tried to restart my Desktop computer 2X's by turning it off on the tower and finally had to unplug my computer to clear that field. 

I have at one time in the past, contacted a QB specialist by phone and they were not able to help with the problem.