10.6.8: boot and computer slow but can't find the reason. Advice needed!

Hello community

I have an old but normally good running iMac from 2008 (Intel Core 4 Duo, 4 GB RAM). My drive is about 80% full. Today, the computer crashed while watching videos on an external drive in iMovie. I had to force a reboot by pressing the power button. Since then, my Mac behaves very stangely:

Booting to the login screen takes about 5 minutes and logging me in another 5 minutes.
Rebooting anew from the finder also takes that long.
I can start programmes, but everything is lags extremely.
Open windows behave strangely and sometimes aren't displayed correctly. After clicking something, I have to wait for minutes until the computer becomes responsive again.

However, I am unable to identify what causes the problem and I don't really know how to try fixing it. Disk utility says my drive is OK. Thanks for help and advice!

Morgy

iMac (20-inch Early 2008), Mac OS X (10.6.8)

Posted on Jan 2, 2016 12:11 PM

20 replies

chroot

Level 4

1,102 points

Jan 5, 2016 2:22 AM in response to Morgy

If the disk is fine and you can't find a software issue, try resetting the SMC.

Resetting the System Management Controller (SMC) on your Mac - Apple Support

Morgy Author

Level 1

34 points

Jan 5, 2016 2:32 AM in response to chroot

Hello choot, reset SMC had no effect. However, I was able to run "Smart Utility", which showed

disk0 FAILING and "Uncorrectable Errors"

chroot

Level 4

1,102 points

Jan 5, 2016 3:10 AM in response to Morgy

As others have previously mentioned, the physical disk should be replaced. There is no other solution, it's a definite hardware issue.

Morgy Author

Level 1

34 points

Jan 5, 2016 3:15 AM in response to chroot

Ok, thanks to everyone! I think I am well informed now by this thread here and can consider my next steps. I would post again later with further questions.

Morgy

SeaPapp

Level 7

26,492 points

Jan 5, 2016 3:29 AM in response to Morgy

a)Failing hard drives often work in target mode, but will not boot a system.

b) Your superdrive has also failed, which is fairly common, your discs are damaged, and your bootable clone is no good for whatever reason.

Your computer starts, slowly, everything operates, slowly, sounds like a bad hard drive to me.

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10.6.8: boot and computer slow but can't find the reason. Advice needed!