Mdworker process suddenly high CPU usage

Question

Hi All
I've been running Mountain Lion since it was released, upgrading from Lion. I've never had a problem with mdworker until a few days ago when suddenly, the mdworker process started hitting 90% CPU on my iMac.
I've disabled Spotlight, deleted the .Spotlight directories, rebooted the iMac, but each time mdworker . Prior to this, the iMac's CPU temperature was around 43C, with very little CPU usage, but now it is around 60C and 100% across the two cores. The only way to 'get back to normal' is to use :
sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
but of course Spotlight doesn't work at all.
I've used 'sudo fs_usage -w -f filesys mdworker' but I can't see anything that mdworker is perhaps choking on.
Does any have any ideas? I'm racking my brain to remember if I did anything different a few days back that might have caused this to happen, but apart from just normal email and web surfing, nothing else springs to mind.
Help!
Paul

Answer 1

David Losada
This solved my questionRe: mdworker process suddenly high CPU usage     Nov 28, 2012 1:41 AM    (in response to antobal) 
In my case it was the BritannicaBookmark.mdimporter that was a PowerPC mdimporter. But it was not in \library\spotlight but inBritannica 12.0/Ultimate Reference Suite.app/Contents/Library/Spotlight.
You can see what spotlight plugin is choking on you by selecting the mdworker process in the Activity monitor and click on Open files and processes.
Sounds helpful, but I don't see "Open files and processes" in Activity Monitor. If I click on inspect, I get a choice to "Sample" processes. I get a system log that is a bit beyond me.
antobal Brussels, Belgium
Re: mdworker process suddenly high CPU usage     Oct 3, 2012 12:47 PM    (in response to asfafa) 
I was having the same problem, and a second level support person at Apple helped me solve the issue today:
Look in the \library\spotlight folders both at your drive root level and your user folder. These folders contain spotlight plugins, with the extension .mdimporter. Some of those plugins, if defective, can make the Spotlight indexing processes to run continuously.
Also sounds helpful, I found .mdimporter files in my system library, but nothing looked unusual. I didn't see a spotlight folder in my user library. I looked in application support and several other places. I used Onyx to repair permissions, rebuild spotlight index, clear caches etc, rebooted, it seems to be OK now.