Are you seeing a (like 1000.50), or is the launcher just stuck on a loading circle ?
Sometimes the error isn't about your files; it’s about your "digital ID" (your IP address) getting tripped up by Rockstar’s servers.
The most common villain in this story is a corrupted local profile. Sometimes the Social Club just forgets who you are.
Software can be stubborn. If the Rockstar Games Launcher doesn't have the "permission" to talk to your hard drive, it simply gives up.