FiletypeID is free portable tool that identify the type of a file by examining its contents. And so even if you’ve found a mystery file which has lost its extension for some reason, FiletypeID may be able to tell you what it is. Drag and drop a file onto it, click the “Analyze” button and that’s it: within a second or two you should see its file type listed: executable, a PDF file, an image, MP3 or whatever (the program uses the popular TrIDLib library and so supports a lengthy list of formats).
[advt]If the program isn’t entirely sure what type of file you have, for instance, it may display several possible matches. And while FiletypeID is generally good at identifying file types, that doesn’t always, tell you their purpose. It can provide useful information in many situations, and if you do ever need to identify a mystery file then it can be handy.