1. If this occurs when attempting to move Sims into the lot then restart your game and check if they are shown as being resident in the property. The move might have failed in which case you should follow the proceedure in this topic.

2. If you have successfully played the lot before and the game did NOT crash when saving then there is a problem with the lot rather than the Sims. Evict the family and remove the lot from your game by following the proceedure in this topic

3. If the game had crashed upon exiting in a previous time when you played the lot or you experienced problems with the family when they occupied a different house then it is likely that the SIMS are corrupt. If you're particularly attached to them then it may be worth checking for a bad custom content file before you delete the family, otherwise try moving the lot plus the Sims into your Lots & Houses Bin and then deleting them.

4. If you find you are unable to remove the lot in game then follow the other steps listed in this topic