This question turns up every now and then, so I'll put this info in here as a sticky topic. Please don't reply to this topic. If you have another question about the elevators, start a new topic. If you do know about a new solution to one of these problems, send me a PM.
- Skyline: Sometimes the groundfloor button doesn't appear at all. This is one of the unsolved random bugs of the game. If this happens, you can either use the console to "noclip" into the elevator, or reload a previously saved game (this doesn't always help, sometimes you'll have to go far back to get a working save file). Another option here is using the air vents: Go down to the computer room in the basement and climb through the vents. After you have called the elevator from another floor, the ground floor button usually works again. Remember to distract the guard (be careful if you do it by drinking from him, he doesn't refill), or enter the basement via the sewers.
- Empire hotel: From my observations, the actual trigger area for the button is smaller than the area in which you can see the use button icon. So either move around carefully until you find the spot where it works, or reload and try walking up to the elevator from a different angle. Noclipping doesn't help here as every level in the Empire hotel uses its own map file.
- Asylum and Red Dragon: Luckily the problems here occure only very rarely. Your only options here are noclipping or reloading. There is no way around the elevator.
