Sometimes I notice CPU load for no reason and I see in Activity Monitor that VTDecoderXPCService is using 15-30% of CPU.

After I restart Safari it is ok for some time until it happens again.

Any ideas? Could be flash related? When this happens there is no videos loaded in tabs but maybe one play triggers the problem.

Should I just uninstall Flash from the system? I'm still on Mavericks and Safari 7 - will youtube play without issues via HTML5? I heard they made it work on Safari 8, not sure about 7.

Thank you

  • it's a video sandboxing service, according to Google - QuickTime, perhaps camera-related
    – Tetsujin
    Commented Feb 6, 2015 at 18:52
  • 1
    ok, thank you... I'll observe if this happens after the camera is in use... also maybe I will disable camera when I'm not using it with iSight Disabler script... for paranoid and performance reasons :)
    – davidhq
    Commented Feb 6, 2015 at 19:54
  • Most likely this process is related video playback. Also, you won't have any performance improvement from unloading a driver of an unused piece of hardware.
    – Alexander
    Commented Jun 18, 2015 at 0:40
  • 1
    I don't know exactly what it's being used for, but it does appear to be a legitimate part of the operating system. Both VTDecoderXPCService and VTEncoderXPCService are within /System/Library/Frameworks/VideoToolbox.framework.
    – duozmo
    Commented Jan 14, 2016 at 4:47
  • 1
    In my Case Boom 2/Boom3D Equalizer caused this issue.
    – CodeBrauer
    Commented Dec 7, 2017 at 9:55

13 Answers 13


I did a spindump via the activity monitor and so i found the resposible app. In my case it was Firefox (HTML5 Vids)

enter image description here

  • 2
    Thanks! Running spindump pointed me at the culprit; restarting chrome sorted me out
    – ptim
    Commented Dec 1, 2016 at 4:53
  • 1
    Restarting Chrome works for me as well. I find this service always goes crazy after attaching a photo in gmail. It might be related to the photo selector window?
    – ScottyG
    Commented Dec 7, 2018 at 17:49

Quitting iMessage ( Messages ) seems to kill the process.

  • 1
    I had Messages.app open with a chat session displaying an Instagram video snippet on loop. Closing the Messages.app immediately relieves CPU usage for the VTDecoderXPService process and the WindowServer process.
    – David H
    Commented Mar 12, 2018 at 23:05

According to this website, the VTDecoderXPCService is called to sandbox applications that might play quicktime or other video content.

You could try quitting your applications one by one and seeing which ones are calling that process.

For me, it's usually Safari or iTunes and since you have it taking CPU that's pretty measurable, it should be easy to track down what's sending work to that part of the OS. It could be Messages or Photos, too.


I tried and in my case is the app Photos, and also there's this photoanalysisd process is running a lot of CPU too. MacOs sierra and 2011 MBP


Don't have a right solution. But I also noticed that Messages.app is the problem here. After I quit the Messages app the process exited. Before that, even after killing it, it'd respawn each time.

  • 1
    This does not really answer the question. If you have a different question, you can ask it by clicking Ask Question. You can also add a bounty to draw more attention to this question once you have enough reputation. - From Review
    – IconDaemon
    Commented Oct 28, 2016 at 0:20
  • 1
    @IconDaemon This does not answer the question in full. But I'm providing a clue. Maybe someone else can elaborate on that. And I don't have a different question. In no way this was a question and it didn't even have a question mark anywhere.
    – moltar
    Commented Dec 4, 2016 at 4:01

To find the program that is using this service, I have used the Energy tab of the Activity Monitor. Identify the highest energy-consuming app. Much simpler than spindumping as suggested in lowrin's answer


I saw this behavior after I accessed the People album in Photos on Sierra. I'm sure it's doing face recognition locally, since Apple bragged about it at the Sierra launch event.

Photos has a "pause for one day" button on the iCloud tab in the app preferences. I pressed that button and everything is now back to normal.

  • Yes, when I killed the process, then Photos notification shows up saying "unable to upload" to a shared album. It seems Photos is running this thing in the background..
    – Magne
    Commented Oct 9, 2018 at 9:55

Quitting FaceTime closed the service for me.


I wrote this guide if you want to limit the CPU usage of the process. It is horribly irritating and I shouldn't have to disable Messages every 15 minutes.


  • While a good idea, it's much more simple to use AppPolice.
    – MiB
    Commented Feb 16, 2021 at 17:23

I had the same problem - VTDecoderXPCService process taking up about 30% of CPU and when I tried to quit it with the Activity Monitor, it just reappeared right away.

I didnt have any video related apps open or tabs in Chrome.

There was a second process called Google Chrome Helper that was also taking up about 25% of the CPU. Weirdly, once I quit that one with the Activity Monitor the VTDecoderXPCService disappeared as well.


My issue was Messages app, but it happened because there was a link to a YouTube video that in my messages. I played back the embedded version, and that's when the CPU usage spiked.


Mac OS X Sierra 10.12.6 on 4 core, Corei7

Facetime and PhotoBooth both launch the VTDecoderXPCService process and consumer ~30% CPU time.


This issue occurs for me when I upload a photo to a website using Chrome. Quitting Chrome solves the issue, though temporarily till I do it again. Very painful!

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .