QuickTime provides a convenient way to play multiple video and audio formats. The player keeps a list of recently accessed content so that you can quickly pull up your past history. You can, however, remove the history entries to protect your privacy. In most cases, you can simply clear the history with a few simple steps, but if this doesn't work, you may have to take additional troubleshooting steps.
Launch QuickTime, and then click the "File" menu.
Select "Open Recent" from the menu.
Choose the "Clear Menu" option. This deletes all of the recently viewed files in QuickTime.
Click the "File" menu, select "Open Recent," and then check to see if recently opened files still appear. If they do, restart QuickTime and check again.
Play a new MP4 file after clearing the history if you find that your recent activity still displays.
Close QuickTime, and then remove it from the Dock if you're using a Mac. Open QuickTime again to ensure that your past history gets cleared.
Click the Apple icon on a Mac, select "Software Update...," and then choose "Update All" to update your system. On Windows, bring up the Charms bar, select "Search," type "Apple Software Update," and then select "Install" to download any available updates.
Clear your recent history on your iPhone running iOS 7 by clearing your Internet history. Select the "Settings" app, choose "Safari," and then select both the "Clear History" and "Clear Cookies and Data" options. Keeping your software updated can resolve many performance issues, and may also prevent the need for advanced troubleshooting in the future.