@leanansidhe47 - The Mascot is classified as a Global Role Sim and is usually a homeless NPC in whichever world they appear. They won't always, at all times, actually be on the map anywhere as homeless NPCs will go into hibernation when they aren't being simulated.
If you are using NRaas mods, you might try MasterController's Invite Over command to see if that brings her up on the list and pushes her to go to wherever your active sim is. But on a different play session/different trip to Uni World than the original one, the Mascot(s) spawned may not be the same sim(s).
Without mods, the best you would be able to do is keep looking for her or anyone else who is wearing the distinctive mascot costume.
Although this is not what you asked about, I would be more concerned about why your computer shut down entirely in the middle of a game session. Does this happen often and was it a surprise, or did it shut down for some known reason unrelated to the game?
