As of July 2021 this method works again. I successfully tested both LaunchRDR2.bat and desktop shortcut for PlayRDR2.exe on
- RGL 1.0.42.369
- RGSC 2.0.8.5 - after every RGL/RGSC update you should redo steps from "Required setup steps when connected"section
- RDR2 build 1436.25 (Blood Money/DLSS update)
- Epic Launcher 12.2.10-16850973
Be advised that although Rockstar is commited to supporting offline mode it may inadvertently break again in some future RGSC update. Offline mode launch with saved RGSC credentials used to work until Rockstar broke it in October 2020 RGL update, then after my ticket they fixed it in November 2020 RGL update. At least now there is "alternative offline running method" by EMPRESS V2 & Mr Goldberg.
This method works if you legitimately bought the game from Epic Games Store and want to play through RDR2 story mode offline. The method (after modifications for specific store) and Troubleshooting section are also applicable to RGL and Steam RDR2 versions.
TL;DR - recent Epic Game Launcher and Rockstar Game Launcher versions explicitly support offline mode and RDR2 story mode can now be started without internet connection using only saved RGL/RGSC credentials. Moreover, it can be started from custom desktop shortcut for RGL without running Epic at all as long as this shortcut has correct saved Epic credentials as parameters - they can be obtained from RGL logfile.
