Problems with Launcher (Steam User). Solved

Since Saturday I have been having problems with reinstalling the Store Content. At first I thought it could be the files I had was misplaced. Yesterday I deleted the Store Content in my Downloads Folder and reinstalled, thinking it could be that the files could have became outdated (The oldest files on my laptop dates from August 2017). Today, I reinstalled the remaining items I had left, installed the items I downloaded yesterday and deleted the Custom Content I don't use before playing. Unfortunately, the Store Content still hasn't appeared. So I Saved and Quit before asking my brother for advice. He suggested that I uninstall The Sims 3 from Steam beore reinstalling (I use Steam primarily for The Sims 3, but I use the CD Keys on Origin). But I kept getting an error message every time I started up the Launcher saying "There was an error during Startup. Please refer to the Log". My sister suggested an uninstall, reinstall and a restart, and did that. Here's what I have:

Expansion Packs
1: The Sims 3
2: The Sims 3 World Adventures
3: The Sims 3 Ambitions
4: The Sims 3 Late Night
5: The Sims 3 Generations (The list on the My Page doesn't show, but I have Generations installed)
6: The Sims 3 Pets
7: The Sims 3 Showtime
8: The Sims 3 Supernatural (Like Generations, this EP doesn't show up on the My Page but it is installed)
9: The Sims 3 Seasons (Again, this EP doesn't show up on the My Page but it is installed)
10: The Sims 3 University Life
11: The Sims 3 Into The Future

Stuff Packs
1: The Sims 3 Design and High-Tech Stuff
2: The Sims 3 Fast Lane Stuff
3: The Sims 3 Outdoor Living Stuff
4: The Sims 3 Master Suite Stuff
5: The Sims 3 70's 80's and 90's Stuff
6: The Sims 3 Movie Stuff

Mods
1: NRaas Overwatch
2: NRaas Story Progression
3: NRaas Master Controller
4: NRaas Tagger
5: NRaas Traveller
6: NRaas Porter
7: NRaas Go Here
8: NRaas Vector
9: NRaas Careers
10: NRaas Mover
11: NRaas Error Trap
12: NRaas Relativity
13: NRaas Relationships
14: NRaas Hybrid
15: Supernatural Babies
16: Longer Seasons
I also have "The Mod That Can't Be Named"

Custom Content
Skysims 171 Retexture
Skysims 178 Retexture

Store Sets
1: Bohemian Garden
2: Tip Top Toddler Collection
3: Kids! 2010
4: Registration rewards for Ambitions, World Adventures, Pets, University Life and Into The Future
5: The Free Sets; Halloween, Winter, New Years, Valentine's, St. Patrick's Day, Autumn, Lunar New Year and the Sports sets

I also have a number of items from different Store Sets

Store Worlds
1: Riverview (Received when I registered the Base Game to Origin)
2: Hidden Springs

I haven't had this problem before now. But I am currently trying to see if the Launcher being updated on Steam helps resolve the problem. I will update with the result