[WhyCause]

PyInstaller-made executables also used to have a habit of getting flagged by security software as malicious (maybe that's why you couldn't run it?) -- apparently, so many malware writers used it that it ruined the party for everyone.

Fortunately, that was only the 32-bit version of Python 2.7. Using 64-bit versions or Python 3 was enough to not get flagged as malicious. I figured that out when I decided I didn't want to teach myself Go just then to deploy something that had worked the day before.