Re: Can't save cas/simmers/households library or upload to gallery.

@Rosenkrantz1206  When you view your sims within your library, do you have the option checked to include custom content?  Sims can be marked as having cc even after you've removed it.

If this isn't the issue, please go into Documents\Electronic Arts\The Sims 4 and move the Tray folder to the desktop.  This will remove all your in-game library items; you can put them back later.  For now though, please just try saving a household to the library both through the in-game function (i.e. saving one you've created or are playing with) and by downloading a new one from the Gallery.  Let me know if either one works.