Occasionally, you may encounter a file with no file extension. It may have been saved incorrectly or the file extension was accidentally removed.

When a filename does not include an extension, your operating system may not be able to identify the file or open it. Fortunately, many file identification tools allow you to determine an unknown file's type. For example, you can drag and drop your file onto FileInfo.com's home page to identify its type. You can also use one of the following programs to determine your file's type:

• File Viewer Plus (Windows)
• File Viewer (Mac)
• File Viewer for Android

After identifying your file's type, rename the file to use the correct extension. For example, if your file is a Microsoft Word document, add the .docx extension to the end of its name. Then, open the file as you would normally.

NOTE: If none of your files have file extensions, your computer may not be configured to show file extensions. View instructions for displaying file extensions in Windows and macOS.