QTKitServer Safari Web Content

Check /Library/Internet Plug-Ins

If you see: DefaultBrowser.plug-in In the Internet Plug-Ins folder, move it to the Trash.

Quit and relaunch Safari and the Activity Monitor > CPU.

See if you still see the Safari Web Content not responding in red.

I have the same thing, and Safari 7 is working for me too. Depending on how you look at it, it's either normal or a bug.

Try this...

Open the Finder. From the Finder menu bar click Go > Go to Folder

Type or copy paste the following:

/Library/Internet Plug-Ins

Cllick Go.

It helped me, I'm hoping it will help you.

Make sure to quit and relaunch Safari after you move the defaultbrowser.plugin to the Trash

Then check Activity Monitor.

Ok.. you can select the QTKit Server in the Activity Monitor the click the force quit icon (circle with an x) top left in that window.

Doing that also speeded up Safari for me!

I did all what you say. Delete DefaultBrowser.plug-in from /Library/Internet Plug-Ins,

restart Safari, check Activity Monitor

But, it was help only for few hours.

I install Mavericks over the 10.8.5. If i will do clean install, help it to me?

Carolyn, I've been having this problem. When I updated to 10.9 I had about 20 safari windows open, many of them with lots of tabs. I tried your suggestion to delete

DefaultBrowser.plug-in from /Library/Internet Plug-Ins and then rebooted.

Before rebooting I had about 20 QTKitServer... not responding in Activity Monitor. Now, after startup and opening all the safari windows there are 10. They didn't show up all at once and usually (always?) showed up black and then going red in a minute or so. The good news is they all use < 0.1 CPU seconds before they die.

One thought I had is that I'm using the ClickToPlugin extension and than might be killing something that upsets QTKitServer. I also use Little Snitch to block unwanted outbound messages. I'll check both and report back....

Maybe I must delete something else? In /Library/Internet Plug-Ins I have

Here https://discussions.apple.com/thread/3245315 I read I must unstall 3ivx. It can help me? (I think it is not real help, because these topics was in 2011 year)

I did a clean install of Mavericks and I am having this problem.

If clean install didn't help ,the best way is not pay attention on this bug...