I know I am late, but I had the same issue after switching from development branch to the old branch and wanted to share my “fix” .
Suiciding didnt help, rebooting didnt help, removing local game data didnt help, verifing game cache integrity didnt help. etc. etc.
Turns out I had to remove the local game data, AND manually remove the entire folder " C:\Program Files (x86)\Steam\SteamApps\Common\Rust"
After you’ve removed that, you’ll notice that this time, the Rust download is a lot bigger. Redownload the game and voila! Works
Probably the same fix as rebuilding the keybinding data, just more rigourous