BearPup sometimes wants to open a file in one program, and other times open it in another. He asked the Answer Line forum for an easy way to do this. Windows uses a file’s extension–the part of the ...

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 ...

Red Eye Rose received a file with a strange extension. She doesn’t know into what program she should load it. Neither does Windows. I doubt that anyone knows all of the file extensions used since the ...