Game crashed when trying to leave Sixam

SayBooooo​  I'm not sure either, and there are too many possibilities that can't really be proven.  But the important thing is that your game works now.

puzzlezaddict​ Interesting, I just tried to explore the wormhole again and managed to return from Sixam! Not sure what fixed this.

SayBooooo​  I don't know of any bug with Sixam specifically, or with returning from it.  But it's easy to test again, without saving.  Please let me know whether the game crashes again.

It's entirely possible that whatever problem caused the crash won't happen again, for example if some item on the lot broke (in the sense that the game couldn't load it) the last time around but is fine this time.  So you could also just play as normal and hope it works.  But keep backups in case you need them.

Thanks puzzlezaddict​ , I'm able to revert to a save before going into Sixam.. Would going back to Sixam still crash? Is that a known bug?

SayBooooo​  Please try reverting to a save before your sim went to Sixam, and see whether you can load the lot you'd be returning to when leaving Sixam.  The question is whether there's now a problem with the lot, and the game can't load it and crashes.  Here's how to load a backup save:

https://sims4.crinrict.com/eng/2014/09/recover-backup-save-game/