You shouldn't need to reinstall the game itself. You might try instead resetting your Sims 3 folder.
Sims 3 - How To: Create a New Sims 3 Folder - With Photos
https://jadekitten.net/mfhot/index.php?topic=60.msg176#msg176This may help with getting Riverview to finally stay installed.
But also, saving your families and houses - separately to the library and starting them in a new save may help as well.
Add your empty houses to the save and edit new doors/windows etc. so it's functional and then add the families back.
When I have had saved games filled with CC and removed that CC or even some of it. I usually delete that save and start a new save. This way it removes all traces of the CC regardless if it's good or bad.
Saving the Sim families to the library keeps their traits, skill and career levels, but will loose relationship connections outside of the household.
You can fix relationship connections with Nraas MasterController:
To Fix Relationship -
From active Sim, select Nraas > MasterController > Intermediate > Long Term Relationship:
By Category > Homeworld > Select Sim from list > Select Status > Enter a set number of days.
They will also loose case count, for example if they are in the PI career.
