Very high memory and CPU usage by the OS X Dock

I have a very annoying problem with the Dock process - after more than a few hours of uptime, the memory usage will spike to more RAM than I have. The process will begin to thrash the hard drive at the maximum speed that it can (according to iotop), and it will regularly use more than 100% of CPU, which I guess means that it's using more than one core at the moment. The number of threads in use ranges between 5 and 12.

Even though I have 12gb of RAM, I regularly start running into the swap file, and I have to kill the Dock process. This resets the amount of memory that it uses to about 60mb, but within minutes, it will be taking up more than a gigabyte again.

Because of the high memory usage, CPU usage and swapping, this regularly makes my computer entirely unusable. Given that this is my main work machine, I will have to probably reinstall it soon if I cannot find a solution, and I can only hope that reinstalling it will actually fix the problem. Has anyone encountered a similar issue before?

Solution 1:

If you are using Parallels Desktop 6, this article may apply :
Dock using 100% CPU after OS X 10.6.8 update for Parallels 6 users.
The details can be found in this Parallels KB article:
Mac Dock consuming 100% of CPU core after upgrade to Mac OS X 10.6.8.

Adobe Updater in the dock is also cited as a possible cause.

To completely reset the dock back to the original factory settings, remove the files "com.apple.Dock.plist" and "com.apple.Dock.db" from your /username/Library/Preferences/ folder, and then log out and back in again. Be sure to write down what you have in the Dock, so you can set it up again just as you had it.

Solution 2:

This can also occur with VMware Fusion 4.1.1. If I quit VMware, the Dock process returns to normal CPU usage within a few seconds.

Solution 3:

Another cause for Dock to consume >2GB real memory...

I had selected a set of photos to cycle as my desktop background. Some fo the images were rather large TIF images. This caused Dock to consume extremely large amounts of memory and CPU. Since the problem depended on image, it would seem to come and go and was therefore, hard to tie down.

Reverting to a single, normal sized JPG solved the problem completely.

Solution 4:

I recently discovered consistent ~20% CPU usage on my MacBook Air was caused by the "Change picture" setting being enabled and set to "Every 5 seconds".

Disabling that setting caused the Dock process to drop to virtually idle.