An Outlook user wants to know if he can add more file types to the All Files (*.*) filter.

This is not possible, but you don’t need to add more file extensions to the list to filter by extensions. You just need to type the extension in the file name field and press enter to filter the list. For example, if you want to see only PDF files, type *.pdf and press Enter.

You can also filter by partial filenames, with or without extensions. For example, ca* will file all files that begin with Ca.

Oh, and this works in the File Explorers in most applications.