Macbook Pro won't play mp4 files and sound controls no longer work

I am not able play .mp4 files and get "An unknown error occurred (-101)" In addition, my external speakers and headphone outputs do not show up on the SOUND dialog in System Preferences.

MacBook Pro 13″, macOS 10.15

Posted on Aug 27, 2020 7:05 AM

Similar questions

All aplication crash when playing audio Good afternoon Gents, I have just recently updated to OS Catalina. All was running good, when sudenly macbook crashed, restarted and after that I can not play video in Safari or Chrome. In chrome it says Error in playing audio, restart you computer. Any application like: Music, VLC player or 5kplayer will crusch when I try to open any video file. Do you have any idea how can I sort this out?
1354 5
Macbook Air (2011) - sound and video not working since rebuild with High Sierra Hi I have had this Macbook Air working perfectly since new upgrading the OS each time until it landed on High Sierra (as it can no longer run newer versions) and I took the bold (foolish?) step of reinstalling the machine from High Sierra download media and now Sound and Video will not play on the machine. The laptop speakers dont work (nor appear in sound Settings), but headphones do work OK and I can't play any video files - neither those from my Photos library (HEVC 1080), or even AVI/MP4 movie downloads. Quicktime reports this error: The document “MVI_2520.AVI” could not be opened. An unknown error occurred (-101) I have tried resetting the PRAM and the Baseboard with the funky keyboard presses loads of times as this is what most suggestions seem to be, but no joy. Now, all of this has been working fine up until the rebuild, so I can only presume that there is a difference between building a machine from scratch as High Sierra and upgrading it release by release each year to High Sierra. Has anyone got any suggestions for me as I can find no clue on the Internet how to fix this? Thanks in advance for any assistance. Gary
184 5
Preference Error: could not load Sound preference pane When I click on the 'Sound' button in the System Preference Panel I get a spinning wheel and then finally the statement: Preference Error: could not load Sound Preference pane Discovered that iTunes quit playing songs, takes longer to even load up iTunes. Tracked the bigger problem down to Sound Preference messed up. Also experincing some extreme slowness with the new Safari update 14.0. Youtube doesn't work now. I did also install the latest security update several days ago. (Both updated when they first appeared just a few days ago). Now I am suffering these problems. I'm on MacOS 10.14.6. Rebooted multiple times, ran Utility Disk, ran Apple Diagnostics using [Option + D]. None of that helped. My system has been working fine for years. Any suggestions?
15476 9

1 reply

mario49

Community Specialist

Aug 28, 2020 12:29 PM in response to EMcDanel

Hi EMcDanel,

We see you're having some audio hardware issues with your Mac. Does restarting help? If not, let's try resetting the NVRAM and SMC to see if the issue persists. We have included links to resources showing you how to do both below.

How to reset the SMC of your Mac

Reset NVRAM or PRAM on your Mac

We hope this helps.

Take care.

This thread has been closed by the system or the community team. You may vote for any posts you find helpful, or search the Community for additional answers.

Macbook Pro won't play mp4 files and sound controls no longer work

Welcome to Apple Support Community

A forum where Apple customers help each other with their products. Get started with your Apple Account.

Learn more Sign up