After I ran the launcher.bat, it stopped working for me, as well.
At that point, I dug into the Obsidian folders on the USB drive to find Obsidian.exe. Then I created a shortcut, which I copied to the main directory on the drive. It runs like a top for me now…no need to run the launcher.bat every time. (It appears that the requisite folders are all created in that first instance of running it.)