A .exe file (executable file) is a type of computer file specifically designed to run programs on Microsoft Windows operating systems. It contains instructions that the computer directly executes when you open it, launching applications, installers, or utilities. This differs from documents like .pdf or .docx files, which store information but don't run complex code themselves. Whether opening a .exe file is safe depends entirely on its source and intent, as these files have the capability to perform almost any action on your system, including potentially harmful ones.

You encounter .exe files constantly when using Windows; for example, opening Word runs winword.exe, and launching a browser might involve firefox.exe. Software installers downloaded from official websites (like setup.exe for Adobe Reader) are legitimate examples. IT administrators frequently manage .exe files when deploying business software across company networks. However, an .exe received unexpectedly via email or downloaded from an untrusted website poses significant risk.

Legitimate .exe files from trusted sources are essential tools. However, the ability to execute any code also makes .exe the primary file type used for distributing malware like viruses, worms, and ransomware. Their safety hinges entirely on trusting the source: .exe files from official app stores, reputable software vendors, or your own IT department are generally safe. Conversely, unsolicited email attachments, pirated software sites, or unknown downloads often carry malicious .exe files. Always verify the source and use updated security software to scan before opening any downloaded .exe, and be wary of unexpected files. This inherent risk necessitates caution.