The “VTDecoderXPCService” process generates a CPU load of over 100% on the Mac - what to do?

The process VTDecoderXPCService sucks properly on the CPU. But what is the cause of this process?

Today I learned something again. My MacBook Pro suddenly became quite slow, keystrokes took seconds and the mouse pointer only moved in slow motion. A look at the "Activity Monitor" utility - permanently installed in macOS and to be found under "Applications" -> "Utilities" - immediately showed me the cause: A process called "VTDecoderXPCService" has the CPU heavily besieged and almost continuously over 100% of the computing time drawn.

The process VTDecoderXPCService sucks properly on the CPU. But what is the cause of this process?
The process VTDecoderXPCService sucks properly on the CPU. But what is the cause of this process?

What is the process doing?

A quick research on the Apple Support forums showed me that I seemingly not the only one am where the process surfaced. Apple's rationale is as follows:

The VTDecoderXPCService process is responsible for all sorts of things that come with Quicktime related. It "sandboxes" these processes and ensures that they cannot access unwanted memory areas. So if audio or video playback is involved in any way, then the process on macOS Sierra is likely to be involved.

In my case, it was almost clear to me which program was responsible for this, because further down I found the process "" and this - so I assumed - downsizes the videos from my photo library, to upload them to iCloud. I closed "Photos" as a test and the Mac promptly ran again without snail mode.

Troubleshooting with activity monitor and program switcher

However, according to the Apple support forums, a webcam, video display, or similar can also trigger the process. So you should think about what is running on your Mac that might have called this process. Terminating programs at a time interval helps to check which program could be responsible. You can see which programs are running by pressing "cmd" + Tab on the keyboard.

What does the kernel_task process do?

If you are wondering what the top process in the screenshot called "kernel_task" is doing, which also generates over 100% CPU load here: This process intervenes when the Mac's CPU gets too hot. Then the processes are interrupted and only processed piecemeal so that the CPU can cool down. The result is that the Mac becomes very slow. If you provide better ventilation and cooling, the CPU load of the kernel_task process drops again.

By the way, I can recommend the "iStat Menus" program to keep an eye on the CPU load and the temperature of the CPU. With this you can show a small graph and the current temperature of the CPU in the menu bar, which is very practical.

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12 comments on "The "VTDecoderXPCService" process generates a CPU load of over 100% on the Mac - what to do?"

  1. It takes a long time and I can't turn it off because the process keeps turning on. How can I turn this off permanently.

    1. Hello Teresa! How to deactivate it permanently, I don't know either. But that wouldn't make sense either, since the process converts things in the photos media library. They should be done at some point. For this reason, my recommendation is to simply let the process run through overnight. The next day, the Mac should have done everything and run smoothly again.

      1. Thank you Sir Apfelot! So I do, I hope this finally stops. So far I've never had the problem. I've been experiencing this since reinstalling my MacBook Pro.

        1. Well then, I'll keep my fingers crossed that he'll be done with it soon. Usually annoying with normal work. :)

          1. It's awful, I can't even write that answer to you. It does not stop. Before I rebuilt the Mac, there weren't any such things, even though I made a lot of videos with my Iphone. Maybe that's another cause?
            I would be grateful for a tip. Heartily

          2. Hello Tessa! My suggestion would be to maybe reinstall macOS High Sierra over it. No data is lost as only the system files are rewritten. But maybe that will help with your problem. Otherwise, I wouldn't know from now on what else could be done. Are you sure that it's the VTDecoderXPCService process that keeps your Mac paralyzed?

    1. ... once everything has been calculated, it stops again. Depending on the size of the photo library (and other factors) it can be done quickly or it may take a while.

  2. I also stumbled upon this behavior today. My still fairly new iMAC Pro with OSX Mojave has been paralyzed for 5 hours, I can't believe it. I didn't think that was even possible. A computer with 10 CPU cores and 64 GB of RAM is brought to its knees by OSX. Breathtaking. My activity meter shows:

    VTEncoderXPCService: 507.4%
    VTDecoderXPCService: 359.6% VideoConversion… 98.1%

    What is Apple thinking here? The term "annoyed" doesn't in the least express the thickness of my neck I'm writing this post with. It's not just about the fact that I bought a high-performance computer and paid dearly to work with it - and not about somehow gluing together stupid photos that are uploaded to my iCloud via my iPhone into non-ordered, absurd pseudo-videos. It's about computers not being ready when you need them. Not even a message to the user is worth it to the Apple gentlemen. Truly a very unique "user experience" - which I would gladly have done without...

    By the way, I am writing this message on a Windows notebook, on which I spent the whole afternoon looking for an explanation of the behavior of my computer.

    1. Yes, it doesn't matter how many cores you have when converting. They are all simply exhausted to the limit ... of course it is a bit faster with 10 cores, but the process still paralyzes everything. The best thing is to have a cup of coffee and let the computer work. Then maybe try a restart and see what happens. Everything was fine for me after converting the media library and nothing has happened in that direction since then.

  3. Hi all,
    I believe that this process is only related to an update. When rendering videos (Photo or iMovie) the system collapses, so that smooth rendering is not possible. Ending the process or just waiting won't do anything. Even when I open Youtube in Safari, playback stutters.
    It works a little better with a memory manager, but it cannot clear more than 3-6%. With 8GB of RAM that equates to just 300 MB ...
    Thus, the VTDecoderXPCService process not only cuts away CPU load, but also RAM!

    I've only had this phenomenon since the last major update.
    (Macbook Pro 15 ″ Mid 2010, i5, 2,53GHz, 8GB, SSD 750GB)

    Since then, working has not really been possible - what was Apple thinking? For the first time I have to close all unused processes / apps in order to be able to work halfway. 16GB are not possible to upgrade according to forums and Apple.
    Does anyone have a real solution?

    Thanks and regards Joe

    1. Hi joe! Have you ever rebooted and left the Mac on overnight so it can finish the conversions? For me, after a few hours, the magic was over ... At the moment everything is running smoothly ...

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