PrintUI and icdd Abnormal CPU Usage macOS

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This was driving me crazy and I did not find many information on it online so I decided to share it with those who run into the same issue.

My Macbook Pro running macOS (the latest OS provided by Apple) kept spawning two process’ called icdd and PrintUI. It looks something like this in Activity Monitor and what it’s usage looks like in Activity Monitor:



Woah…97.2% and 96.0% CPU! I’m not even doing anything CPU intensive -_-

I don’t need these processes eating up my power right now and they refuse to end themselves so we need to end them.

Open Terminal and run these commands:

ps -A | grep Image                                                               13:45:18
4047 ??         0:53.82 /System/Library/PrivateFrameworks/PrintingPrivate.framework/Versions/A/PrintUITool
4724 ??         0:20.89 /System/Library/Image Capture/Support/icdd
97497 ttys008    0:00.00 grep --color=auto Image

The little buggers have PIDs 4047 and 4724. Let’s kill em.

kill 4047 4724

Quick details on what we ran above (Click the link for more info):

I killed icdd and PrintUI but that didn’t work! :(

Turns out the they simply respawn themselves if you have Preview (an application loaded on most Macs) running, and sometimes come back even harder!

Let’s kill preview just to be safe. Open Terminal again and run:

killall Preview

What have we learned today?

  • If your computer has a process taking up 90% of the CPU, it’s probably misbehaving.
  • icdd and PrintUI suck.
  • How to kill a process using kill.
  • How to list process’ using ps.
  • How to filter from command output using grep.

macOS Jargon

Turns out icdd is a process that has to do with Image Capture

But wait, I don’t even have any devices connected! Why is Image Capture eating up all those CPU cycles if I don’t have any Images for the OS to capture? It’s actting Rogue, that’s why.

Here is where icdd lives:

/System/Library/Image Capture/Support/icdd

Here is where PrintUI lives: