[peanutgal2600]

This doesn't seem much different than planned obsolescence to be honest.

If he had done this to 100 companies, then he would be considered an enterprise, not a criminal.

[raxxorrax]

Sometimes it is also called SaaS.

[itronitron]

I guess the right way to do this is to setup something to 'auto-install updates' which prompts a call to the contractor to fix the corrupted excel file.