Hey man, I was just having the same problem.
I read this somewhere else, should help by the looks of it.
Im gonna try it now too.
Edit: Step 3 means launch it also without Rockstar Launcher, just go to the main directory and start the .exe yourself.
Edit 2: It didnt work for me. But I found a solution myself.
1. Open Rockstar Launcher and let it update
2. After it is done dont close it, keep the launcher running
3. Open Rage and let it reset it to your backup
4. After its done and launched into settings, close it
5. Start GTA V in Rockstar Launcher
6. Load Rage as soon as GTA V has started
It launches Build 2189 for me, and its working