A file extension is a suffix that is added to the end of a file name after a dot. It is usually two to four letters long. File extensions help Windows and other operating systems to know the standard ...

Microsoft hides file extensions in Windows by default even though it's a security risk that is commonly abused by phishing emails and malware distributors to trick people into opening malicious files.

Microsoft plans to expand the list of file extensions that are banned in Outlook for the web (previously known as Outlook Web Access (OWA)). The list, which previously included 104 file extensions, ...