File name extensions are how OS X recognizes file types, and changing the extension is one way to associate a file with a different program. Sometimes, however, changing the file extension does not ...

Microsoft uses file associations to set default programs for opening different file types on all its operating systems. As a result, when you open a file, be it text, image, or document, on your ...

Back in the pre-Mac OS X and macOS days, Apple’s System 9 and earlier relied on hidden metadata to associate files with apps. File extensions, those bits of text that follow a period at the end of a ...