[GALLERY] 'Content not installed' warning with all content owned

Its happening whenever I try to create a new town or place a new build on any lot

Receiving the same error message. I have no mods and am also playing on PC through the EA app. I have cleared cache and repaired the game multiple times without resolution.

Having the same issues.  It'll even say 'you have everything used in this gallery item' only to say 'Content not installed' when I go to place it.  Still lets me place the room, nothing is missing.  In my case it seems to be happening on anything with the new DLC Legacy and Royalty in it. Which I own, I bought the grand bundle thing even.  Not the biggest deal but really annoying.  

I've never had this issue before, but since the marketplace update and the changes in the gallery I also get this notification. All packs/kits owned, playing on PC.

I've noticed the same thing (PC version - all EP's, Kits and Sets - No Marketplace-Sets). While I can't trace it back to the exact cause, I would say it appeared with the update from March 17th.

My report in the german forum

Same here and it's frustrating. Ugh!!! I love my Sims but I am seriously thinking of rage quitting. First time I am able to play my game after their stupid update and now it's another problem. It is neverending

Thank you. Will try.

Update:  I had my library open for a while on the household I posted about earlier, the one which said Crystal Creations wasn't owned.  I went into CAS and back to my library and the 'not owned' icon vanished in front of my eyes.

This makes me think there may be some kind of delay happening in the messaging system in the background.  Like the game is slow to load the acknowledgement that the pack is installed.   

After the issue had corrected itself on one household, I clicked on another which also had a 'not owned' message for the same pack (Crystal Creations).  It's like the game is registering it too slowly. Or forgetting it's installed.  Adding this household gave me the 'missing content' warning and then caused the grey screen issue where I had to force-close the game with Task Manager. 

It's particularly amusing to get this notification come up on a build I've made and saved to my library! 😆