@cicciofritz @nikitonsky
You will. Everyone does. This is just a thing with software development: you cannot test every use case on every computer in the world. Eventually, someone is going to have a file or process or computer that hits that one function that wasn't made to handle that one thing.

The best you can do is write inherently stable code that checks itself for exceptions and is made to fail gracefully: people are a lot more forgiving of "it said there was an error opening the file and wouldn't open it" than "it crashed without warning or explanation in the middle of my workflow".

The best software developers push stability improvements as part of the efficiency improvements in those small numbers