Live mode not loading and sims not loading - image attached

This is typically caused by outdated mods.  Please see this thread for more information:

https://answers.ea.com/t5/Mods-CC-Issues/MOD-RELATED-Sims-disappeared-from-household-Blue-flashing-square/td-p/8428174

The only fix is to revert to an unaffected backup save.  Here's how to load a backup:

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