Set default program for opening files without extensions in Windows

For some reason, downloading the request / result CSV files for a Salesforce “Bulk Data Load” job returns CSV files with the file extension missing, so you can’t just click to open them. This became super annoying during a troublesome data load so I decided to fix it once and for all.  Open cmd as admin and enter the following:

assoc .="No Extension"
ftype “No Extension"="C:\ProgramData\chocolatey\lib\csvfileview\tools\CSVFileView.exe” “%1"

Obviously substitute in your favourite CSV editor (unless by some bizarre coincidence, you also like CSVFileView and install everything with chocolatey).  Credit for the solution goes to this post on superuser.