"Incorrect Block count" error - advice requested

Hi.. new member here – been a (trouble free) MacBook user now since 2006, but on Sunday I encountered a problem.

I had selected a number of photos for “Export”, in iPhoto, clicked “Export” from the drop down menu… the Mac hard disk made no unusual noises, but revved up quite a bit and then the machine switched off. I realised a t this point that I was running off battery power – the AC was connected but I had turned the power off.

I switched on AC and let the battery recharge for a while, then tried to boot up the Mac. It made the normal ‘start-up’ sound – the grey Apple screen appeared and the activity indicator was spinning. Then – after 80 seconds – the machine turned itself off.

I checked power – all ok.

Repeated the start up…the same result.

Then I searched the Apple Support website and the Mac Forum for start up hints… and ran thru the “basic OSX troubleshooting” steps, from this forum.

Tried to reset the PRAM: I let it chime three times, but the same end result occurred.

I then loaded the install DVD and went into Disk Utility. I highlighted the main drive, to repair disk permissions, but these options were greyed out for the HDD.

So I tried to repair the disk… the progress indicator got to about 40% then it threw out the message:

Incorrect Block count for file Thumbs32Segment.data
(should be 3058 instead of 3016)

Invalid Sibling link

I then tried using fsck in single user mode… it runs thru various checks and fails to repair the mounted disk as it has been set to “READ only” – is this a result of the “Block size” problem, or a separate issue?

I have searched the forum for the terms “incorrect block count” and for “Thumbs32Segment” – no topics found…


What should I try next?

Any ideas or links gratefully received…. Thanks in advance

As you have done all of the things I would suggest to solve it, you have 3 choices that I can think of.

1: Run a hardware check first.
2: Get Disk Warrior/Norton Utilities and try and repair from there.
3: Do a clean install of the OS. How practical this is will depend on whether you have back ups of all you need.

I have repaired this kind of thing with Norton before.

Kevriano said:

As you have done all of the things I would suggest to solve it, you have 3 choices that I can think of.

1: Run a hardware check first.
2: Get Disk Warrior/Norton Utilities and try and repair from there.
3: Do a clean install of the OS. How practical this is will depend on whether you have back ups of all you need.

I have repaired this kind of thing with Norton before.

Click to expand...

Thanks for your reply.

Options 1 and 2, I'll have a go at, tonight. (I have Norton somewhere).

The third option will be a last resort - I have recent backups, but not of the photos that I was trying to save when I had the crash.... ain't it always so?

I will let you know if Norton repairs it.

Cool. It's pretty good, so good luck and let us know how you get on.

Steer clear of Nortons - look at this link:-

Mac OS X 10.4.3: Norton Utilities

The problem with DiskWarrior, which is a great utility, is it costs US$99.00, more than a new HDD. External backup drives are essential as you have found out.

harryb2448 said:

Steer clear of Nortons

Click to expand...

Agreed. Norton is not available for OS X and hasn't been for years. If you do happen to have an old version, it may do more damage than good.

So Disk Warrior or clean install it is then.

Thx for all the responses, so far.

Well....the Hardware Test passed with no problems detected.

The advice regarding Norton was timely. The version I have is from 2004, i have discovered ...and - as you guys have told me -doesn't work with OS X. So I am going to have to invest in Disk Warrior, it seems.

External Backup drives:
I have a backup on an external HDD, from July...which also has OS X loaded. I wondered if it would be possible to start up OS X from the External Drive, and somehow access the dodyg file, on the Internal HDD...but I can't get the "external" system to "find" the HDD of the Macbook. I keep having this nagging thought that I am missing something simple, here...

But I digress....

Disk Warrior it is... I'll let you know when I have it installed and the file repaired!

Sure. Boot from the external holding down option after boot and selecting, a Firewire connection only for a PowerPC, USB2 for Intel will work, go to Utilities, Disk Utility and see if you can select the dodgy drive there. If so run Repair Disk and see what is reported.

If Disk Utility cannot repair, either DiskWarrior 4.2 or a new HDD> Am a fan of DW but it does cost more than a new drive so it is a long term investment.

Thanks guys.

Disk Warrior has done the trick... all repaired, data checked and new backup taken.

Normality has been restored

Our pleasure Brewski. Keep coming back as the forums are just g-r-r-r-reat!

If you like the advice of a particular member, leave positive feedback eh?

Yay for Disk Warrior.
Glad it's sorted.