Missing File Extension

Issue/Question

I have a file that does not have an extension on it.

Cause

When saving a file on macOS computers, most software apps are automatically configured to hide the extension. Transferring those files can cause the app's association to be lost.

Resolution

If You Created the File

1. Right-click the file.
2. Select Get Info.
3. Expand Name & Extension: .
4. Click Hide extension to display the extension.

If the File Was Transferred to Another Computer

1. Check if the extension is intact but hidden by following the steps above. If not, continue below.
2. Right-click the file.
3. Select Rename.
4. Append the proper extension, including the dot (e.g. .pdf, .docx).

Note: If multiple files are missing their extension, but are of the same file type, a third-party program, such as NameChanger, can be used to quickly append the same extension to all files within a directory.