How to Fix QuickTime Won't Play MP4 Video

Updated on May 06, 2022

Utilise Remo Video Repair tool to effortlessly fix MP4 video files that Won’t Play On Mac QuickTime Player Or Windows Media Player. It is built with a powerful repair algorithm that can fix MOV, AVI, MP4, XVID, DIVX, etc. The best thing about this repair tool is that it works on the damaged file in read only mode to repair and generate playable video files.

Help! QuickTime won’t play MP4 files?

“Hi, I have a couple of of MP4 files that will not open and play with my QuickTime player. Is it possible to fix this issue because I want to play these MP4 files with QuickTime? Please help!”

Though QuickTime claims to support MP4 format, sometimes you still can’t open MP4 files with QuickTime or the opened .mp4 file only plays sound without picture or QuickTime won’t play MP4 at all. The reason why QuickTime won’t play MP4 video as well as the solution to play any MP4 file with QuickTime on Mac or Windows is explained below.

Why can't I Play an MP4 File on my Mac QuickTime?

QuickTime won’t play MP4 file properly on Mac OS X can be mainly due to two main parts such as:

  • Codec error: QuickTime unable to open and play .mp4 video saying “MP4 file could not be opened. A required codec isn’t available.” QuickTime only supports MPEG-4 (MP4/M4V).
  • Incompatible devices: Some Macintosh users reported that QT no longer played MP4 file after having updated to latest macOS Sierra. The unsupported drivers or outdated player could be the cause MP4 video not playing on QT.

How to Fix QuickTime Not Opening MP4?

Fix 1: Try Restarting QuickTime Player and Computer

The first thing you need to do, if your QuickTime player is not opening an MP4 video file is by restarting the QuickTime player. If the problem still persists you can try restarting your Mac computer.

Fix 2: Try Updating QuickTime player on Mac

If the above fix was not so effective then try updating the QuickTime player. The error “QuickTime Won't play MP4” might be arising due to an outdated QuickTime player, try updating it. Follow the steps below to update the QuickTime player.

  • In the menu bar of QuickTime player, click on it to check with the QuickTime player version.
  • If you are running an outdated QuickTime player then navigate to the App store application on Mac and click on Update button.

Fix 3: Check if the MP4 is compatible with QuickTime Format

If the above method was not soo helpful in fixing the error, then check if the MP4 video file is compatible with the QuickTime or not. Sometimes QuickTime errors arise due to incompatible MP4 codec with QuickTime.

To check if the MP4 codec is compatible with QuickTime player, open the QuickTime player and click on the Windows option > and select the Show Movie inspector option.

If the problem still persists then you can convert your MP4 video file to the supported QuickTime format.

Note: If a media player, be it QT, WMP or VLC, can't play MP4 files even after the installation of necessary codecs and updated drivers on your Mac, then it clearly indicates that the video is corrupt or damaged. To repair damaged MP4 files on Mac, it is recommended to make use of powerful video repairing tools like Remo Video Repair.

Fix 4: Fix QuickTime Won't Play MP4 File Using Remo Video Repair

Download and install Remo Video Repair tool on your Mac machine and follow the below guide to learn how to fix QuickTime won't play MP4 video issues.

Step 1: Launch the tool, click on Select file and choose the corrupted MP4 video file that needs to be repaired.

remo video repair

Step 2: If you are repairing a MOV or MP4 file then Click on Choose Reference MOV file and select a playable video file for reference to repair corrupted video files.

choose the reference video file

Step 3: Click on the Repair button to start the corrupted or damaged video repair process.

Note: The tool facilitates a Preview of the fixed corrupted MP4 video file.

Step 4: Finally, click on the Save option to get back the repaired MP4 video files.

Characteristics & Benefits of Remo Repair tool

  • Capable of repairing damaged or inaccessible QuickTime MP4 file that is quite large in size
  • It repairs corrupt MOV, MP4 and M4V files successfully
  • Easy to use interface with handy options to fix single and multiple damaged MP4 files
  • Fix QuickTime files of video codecs like avc1, mjpeg, mp4v and audio codecs such as RAW, sowt, mp4a
  • Ability to fix damaged video files on SD card, computer’s hard drive, external hard drive, USB and more
  • Provides the preview of repaired video after the repair has been performed successfully
  • Support all versions of Windows and Mac OS X including Windows 11, 10 / macOS Big Sur