This isn't all that technical either. It mostly occurs when there are outdated mods or custom content installed or some kind of game hiccup.
Here are some tips to try:
1. Move the mods folder to desktop (for testing purposes) - This is to fully make sure it's not outdated mods/cc or some hidden files in the Mods folder. - Read more in the post linked below:
How to Fix Problems with Mods/CC
http://www.carls-sims-4-guide.com/forum/index.php?topic=25031.msg426156#msg426156Mods and cc become outdated as we get new updates for the game. This means you'll need to go through your mods folder to find what needs to be replaced.
2. Delete Game Cache Files (What and How-To)
http://www.carls-sims-4-guide.com/forum/index.php?topic=29288.msg401662#msg401662The localthumbcache.package can be found in the main Sims 4 folder
C:\Users\Username\Documents\Electronic Arts\The Sims 4
Removing the mods folder without deleting the localthumbcahche.package file from your The Sims 4 folder, isn't enough of a test, these two steps need to be done together.
If the mods folder has already been removed, cache and localthumbcache.package have been deleted. Try repair game, or a Sims 4 factory reset and new game without any mods or cc to test.
3. Repair Game:
In Origin, right-click on Sims 4 and select Repair. - Do note this repairs the game's install files for the actual game. It does not make any changes to the saved game files. Meaning that your saved games are safe, they won't be deleted.
4. Try a Sims 4 Factory Reset - (What & Howto)
http://www.carls-sims-4-guide.com/forum/index.php?topic=29292.msg401669#msg401669If any of the above doesn't solve the issue, it maybe caused by a new bug and may be worth reporting it to AHQ.
Report Bugs On AHQ Forum (Where & HowTo)
http://www.carls-sims-4-guide.com/forum/index.php?topic=21467.msg386787#msg386787