mountain lion Sluggish on iMac

I've had this iMac for 10 months now and over time it has become stupidly sluggish. Whenever I turn it on, it seems like it's always reading things off the HDD. In fact all I hear are HDD noises. I really can't put my finger on why it's doing this. The HDD is not full either, I have 400GB of 1TB free.

Symptoms I have are:
- HDD always making noises (like any would do when reading/writing)
- At extreme instances the application would lock up for a second then go back to normal.
- Sometimes There is a very big delay between keyboard presses and what appears on screen.
- Safari takes ages to open a new tab

It seems that something is doing a lot of i/o on the HDD as shown in the two screenshots below:
Photo Album - Imgur

Anything I could do to rectify this?

You might wish to check with Apple care about your hard drive. Apple is recalling certain Seagate 1 TB drives that came installed in the iMac 21.5" and 27" models. (Mid 2011 models) Give them a call and find out if your machine qualifies for a free hard drive swap out.

I did that via the online serial checker they have on the apple site and it says mine is not eligible for the recall. I've got windows installed via bootcamp and that isn't as sluggish as OSX is

OK, just making sure you weren't running with a "sick" Seagate. Download the free maintenance and cleanup program "OnyX" from here and run it in auto mode. The program is free and one that we recommend. Do not use any other "so called" cleaner program as most are snake oil.

Also, you didn't mention how much memory your iMac had installed. Nowadays more memory is required as apps consume more of it when running. Adding memory to your iMac is very easy and not expensive.

The iMac is running on 12GB of ram as listed under my username I'll try out that app and see what it comes out with.

I missed the 12 GB. That certainly should be enough to run most apps. Let us know if OnyX helps.

So I got this notification:


If I did as suggested, would I lose any data?

That could very well be the reason your system has slowed down. And no, you won't lose data by using Disk Utility verify and repair. However, I strongly recommend you do a complete backup of your hard drive before attempting any repairs. Use Time Machine or make a clone with Carbon Copy Cloner or SuperDuper.

I already have time machine running on an external hard disk so that shouldn't be a problem. I was concerned since I'm doing my thesis and although I've got a ton of copies, what I do not have is the time to actually restore any lost data

Anyhow, I ran it and It fixed a couple of permissions and had a couple of "orphaned files" issues were fixed and bloody **** the iMac feels like new, even though it's loaded with files & spotlight is re-indexing everything! The hard disk stopped making noises too, the iMac is completely silent! I'm impressed. Huge thank you!

PS: this came with a western digital caviar. Totally forgot about that.

Great, glad to hear it's repaired. And good luck with your thesis. It's been many years for me since I had to turn one in, and when I did mine it was on an IBM Selelectric typewriter. Yeah, I'm an old horse. ;P

And Onyx is strongly recommended around this way:-


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