Worlds not showing up!

I notice that you said purchase, but not install (this may not have been intentional). But in case you purchased these worlds from Origin or some other source, they still need to be downloaded from the TS3 Store, using a code in the case of credit card purchases, and installed by way of the Launcher or else they aren't really on your computer for use yet.

Or have you already gone through that exercise?

@RosenrotNikki I have a thread regarding a similar issue in the store section see https://forums.thesims.com/en_us/discussion/985379/problem-keeping-store-items-installed#latest

For me, its not only the store worlds but all store items. The trick that i found that works most of the time is to close the launcher, close Origin (not only X the screen but close the program running in the background) and relaunch the game. When I get this problem, in the launcher’s content tab, all store items show up as boxes instead of their pictures and in the installed tab, only venues show up.