When I went to change my Sims outfit in Plan outfits it loaded into CAS and all it showed was a night sky. I can't see my Sim or the clothing options. I tried creating a new sim and got the same thing. Didn't have this issue until the recent update.
My Computer specs: AMD A6-5200 APU with Radeon HD Graphics 2.00GHz
Memory: 8GB 7.43 usable
System Type: 64-bit Operating System, x64-based processor
Windows 10
I had the exact same issue after updating today.
Doing a repair seems to have fixed it for me, so try that.
(Make sure Origin is online, go to your games library, right click on the Sims 4 icon, select "Repair")
