Since when is the cutoff 45 minutes at SFO? I thought it was always 30 minutes. Anyway, just wanted to share my experience because it was not smooth and this might help someone. I arrived around 50 min before scheduled departure, and got into the porter line outside. By the time I got to the guy he said "I cannot check you in, you are within 45 min window, go inside". But my flight was delayed, and was definitely well outside of 45 min window of the new expected departure time. So I go inside to the bag drop machine, and it says that it cannot check my bag. I turned to two different employees, and both directed me to "additional services" at the other end of the terminal, which was a small zoo. One added "you cannot take this flight and will have to rebook". But there was a ticketing agent right next to the bag drop, although there was a small separate line to get to her. Fortunately, this moved fairly quickly, and she was able to check me in without an issue. So bottom line: The bad: the machine doesn't care about expected departure due to delay, the cutoff really is X minutes before original scheduled departure. The good: if your flight is delayed then you are in luck, a human can check you in. Skip the machine and go straight to a live agent.