After an update of Skyrim Special Edition, I got the following error message attempting to run Wrye Bash:
Wrye Bash could not find a game to manage. Please use -o command line argument to specify the game path
The solution was to run the game’s launcher – The update had removed the Skyrim SE settings. Normally, this is what you do anyway when you launch the game through Steam, but I am using SKSE and Nexus Mod Manager, which normally bypass the launcher.