You can identify types of files that you do not want Windows Defender to scan, such as pictures (.jpg) or music (.mp3). You might exclude certain file types so that Windows Defender runs faster by skipping over your music files, for example. Simply type the file extension — you don’t need to include the asterisk (*) or leading period (.) and click Add. To scan any file types you have previously excluded, select the file type from the list and click Remove.