Keviyanaaa Do you have space on your internal drive to test-install Sims 4, at least with the packs that aren't installing properly now? It would be a useful experiment, and it would also potentially allow you to get around the error. This is how it would work, if it worked:
- Install the base game at at least the problem packs to your internal drive
- Close the EA App and kill the EABackgroundService in the Task Manager
- Move the Sims 4 folder that contains the program files to the external (in a subfolder)
- Open the EA App, which will now see the game as uninstalled, and tell it to "download" to the location on the external where you moved the game
- The App may simply verify the files and complete the install process
This works for me most of the time, but the App still tries to fully download certain packs, so I can't promise you that the packs you can't install will work. Since you've tried almost everything else though, this is the next-simplest thing I can think of. It's also just a good test to see whether the packs install properly to a different drive.