New installations of Windows hide all file extensions, except for Windows components, that would appear in Explorer or an application dialog box that displays file names. File extensions are ...

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.

Computer viruses sometimes masquerade as harmless e-mail attachments. The fastest way to spot the interlopers is by their file extension–the letters (usually three) following the final period in the ...