bad blocks = wipe?

Discussion in 'Mac mini' started by zengoth, May 22, 2010.

  1. zengoth macrumors newbie

    May 22, 2010
    techtool states it finds bad blocks on my mac mini (feb 2009) and that i need to wipe the drive? I've been getting bad blocks found ever since I bought this computer. And I am lead to believe that a wipe won't keep more bad blocks from forming. Backing up and wiping isn't difficult - having to reload every piece of software and hardware and file is a huge inconvenience and halts up production time.

    1- is what i have read about bad blocks true?
    2- how do i keep them from forming so I won't have to have downtime everytime a bad block appears?
  2. ADent macrumors 6502a

    Sep 9, 2007
    The drive should be marking the blocks bad internally and removing them from service. I full scan or even better a read/write cycle across the drive should be enough to kick the drive into gear.

    However sometimes the drive does not do its job and a utility needs to get involved. I have never used TechTool, so I do not know how it marks bad sectors or why it has to reformat the drive to do so.

    To stop the bad sectors from showing up get a new drive. Preferably a well understood drive and not the largest drive they make.
  3. bluskale macrumors regular

    Mar 29, 2010
    If you do a reformat and choose to zero out the drive (write zeros over the entire disk), then all of the existing bad blocks should be found and 'taken out of service' as the previous poster explained. This may lower the effective size of your hard drive by a tiny bit, but those points on the hard drive weren't any good in the first place. If there are tons of bad blocks, I believe there is a limit to how many can effectively be shunted aside (before the drive is unusable), although I'm not sure what that limit is.

    So yes, it would be best to reformat most likely. If you keep getting more of them... it may be some sort of defect in the drive.

    If you have an external hard drive (or any external drive) you should be able to simply use a program like carbon copy cloner to duplicate the contents of your drive, reformat the original, then use ccc to duplicate the backup back onto your reformatted drive

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