August 2016
First, as Crnrit suggested, move all of your employess into a house to prevent them being culled each night.
Now that you have them coming in every time you open, if one gets stuck and can't move, do the following:
Press CTRL+SHIFT+C all at the same time.
Type TESTINGCHEATS ON
Press ENTER
SHIFT+CLICK on the stuck sim and choose RESET
See if that lets them move again. If not make sure the path to thier station is not block and the station they need works. You may need to sell and rebuy the station if resetting the sim does not work.
January 2019
My staff was not moving either, but I realized everyone was outside because I locked the door to everyone but my household.
August 2021 - last edited August 2021
Thank you so much DarkAmaranth, you saved my restaurant!