Using Disk Utility First Aid on External HD

Question

Using Disk Utility First Aid on External HD

I have a HGST 4TB external hard drive that's been working great. I have it split up into 5 partitions. I recently upgraded my iMac running Sierra and began to notice that not all of the partitions were mounting on startup. I ran Disk Utility First Aid on each of the partitions successfully. And I think the issue is resolved. However, if I click on the HGST Drive which encompasses all of the partitions and run First Aid, I get the following message:

"First Aid found corruption that needs to be repaired. To repair startup volume, run First Aid from Recovery." The detail window said, "Problems were found with the partition map which might prevent booting." When I ran First Aid from recovery mode, I got the same message saying that there were potential mapping issues. If the partitions are mounting, should I be concerned about the drive, or is this an issue with Sierra, or is it an issue with trying to run Disk Utility First Aid on a drive with multiple partitions? Thanks.

iMac with Retina 5K display, macOS Sierra (10.12.6)

Posted on Oct 16, 2017 4:26 AM

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Answer 1

John Galt

Level 10

155,810 points

Oct 16, 2017 9:21 AM in response to The DrumRunner

Sure, that will repair the broken partition map.

2 partitions (one for time machine, and the other for files)

You can do that. In my opinion though, dedicated Time Machine backup drives are a good idea—no other partitions or data, because a catastrophic failure of the drive can render all its partitions simultaneously unavailable.

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Answer 2

Oct 16, 2017 8:24 AM in response to John Galt

Thank you, John. I realize HDDs are never bulletproof, but since I no longer need all the partitions, I'm wondering if I were to wipe this external hard drive clean and start over with just 2 partitions (one for time machine, and the other for files), would it improve performance and/or reliability? Thanks!

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Answer 3

Eric Root

Level 10

685,257 points

Oct 16, 2017 9:01 AM in response to The DrumRunner

That might help and is worth a try. If the hard drive is failing, the problem may return shortly.

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Answer 4

John Galt

Level 10

155,810 points

Oct 16, 2017 7:57 AM in response to The DrumRunner

As DU explained its partition map is messed up, and a hard disk drive with a corrupted partition map can continue to be used with no apparent ill effect. Whatever conditions caused it to become corrupted are likely to remain and will eventually manifest in more serious problems such as obvious performance degradation or data loss.

.. should I be concerned about the drive,

No more so than any other. Hard disk drives cannot be fixed, can only be replaced, and using any software-based tool to continually monitor its performance will only accelerate its inevitable demise. If the information it contains is valuable to you a reliable and supported backup strategy is required. To learn how to use Time Machine please read How to use Time Machine to back up or restore your Mac - Apple Support. A reliable and supported backup will make the drive's eventual failure a trivial event for which only a small amount of time and money will be required.

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