First Aid Failed.

Started 5 months ago | Discussions
ciaran33 Contributing Member • Posts: 638
First Aid Failed.

Hi, it's El Capitan on a 2011 MBP, an external drive has a Time Machine partition, First Aid fails on that one. The other partitions and the drive itself check out OK. Details say things like "123456 should be 123457". Hmmm?

After maybe 25 minutes, First Aid says "File system check exit code is 8"

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Tom_N Forum Pro • Posts: 18,544
Re: First Aid Failed.

"8 indicates a corrupt filesystem was found during a check, or repairs did not succeed. That's it."

You might be able to repair the filesystem using fsck from the CLI in single-user mode.

https://phonegnome.com/file-system-check-exit-code-is-8-2/

In the past, some commercial third-party tools have had much better success than Disk Utility at fixing corrupted filesystems.  I have read that in recent versions of macOS, many of these tools now have their own GUIs – but call a common macOS API to do the repair work, possibly erasing some of their former advantages.

OP ciaran33 Contributing Member • Posts: 638
Re: First Aid Failed.

Appreciated the reply, quite a bit to get my head around, I imagine these safe modes can see external drives? I'll see how it goes.

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lightandaprayer Senior Member • Posts: 4,001
Re: First Aid Failed.
1

Tom_N wrote:

"8 indicates a corrupt filesystem was found during a check, or repairs did not succeed. That's it."

You might be able to repair the filesystem using fsck from the CLI in single-user mode.

https://phonegnome.com/file-system-check-exit-code-is-8-2/

In the past, some commercial third-party tools have had much better success than Disk Utility at fixing corrupted filesystems. I have read that in recent versions of macOS, many of these tools now have their own GUIs – but call a common macOS API to do the repair work, possibly erasing some of their former advantages.

DiskWarrior should be able to fix it as long as the external drive is not APFS. Back in the El Cap days DW was superior to Apple's Disk First Aid.

OP ciaran33 Contributing Member • Posts: 638
Re: First Aid Failed.

Ah yes, DW, a bit on the pricey side though. I'll see how I get on with the other suggestions first.

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OP ciaran33 Contributing Member • Posts: 638
Re: First Aid Failed.

Any love for Onyx? Dire warnings, or suggestions? I have downloaded but not run it yet.

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JPAlbert Contributing Member • Posts: 970
Re: First Aid Failed.

A time machine backup is just that ... it's a backup of data that already exists elsewhere.

So... if the backup partition is "un-fixable"... you could erase it and "start fresh", because your data STILL EXISTS on the source volume.

If nothing else will make the partition "mountable" again, that may be your best option.

Tom_N Forum Pro • Posts: 18,544
Re: First Aid Failed.

JPAlbert wrote:

A time machine backup is just that ... it's a backup of data that already exists elsewhere.

Not quite.  Time Machine saves old versions of your files, along with copies of the current ones.  Not every old version, but some of them.

So... if the backup partition is "un-fixable"... you could erase it and "start fresh", because your data STILL EXISTS on the source volume.

Your current data "STILL EXISTS on the source volume" (assuming that the current volume is not corrupted).  The old versions of that data don't, unless you're using another method (e.g., "Save As 'Draft1.docx', 'Draft2.docx', 'Draft3.docx') to make it possible to backtrack.

lightandaprayer Senior Member • Posts: 4,001
Re: First Aid Failed.

I think that this is an appropriate thread to mention that problems with Time Machine backups are rather common. . .  Accordingly, I do not rely on it for local backups.  I have other backups made using more reliable software as well as a Cloud backup should disaster hit.  (My area recently experienced a disastrous wildfire which stopped burning around a mile from my home.  The last things that went into my Go Bag was my Mac Mini and external drives.  But sometimes there isn't enough time for such things. . .)

Assuming the OP still has the original data, starting over is the easiest route to take.  But I would check the health of the Time Machine drive before relying on it Just In Case.  DriveDX  is a utility I can recommend but it cannot fix problems that it finds.

OP ciaran33 Contributing Member • Posts: 638
Re: First Aid Failed.

First Aid in Safe Mode did no good, Onyx seems to work only on the system disk, so I've erased the TM volume and re-set TM to the same place. First Aid gives a clean bill of health, though it does take a while to do so. So that's great, thanks for the suggestions.

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lightandaprayer Senior Member • Posts: 4,001
Re: First Aid Failed.

ciaran33 wrote:

First Aid in Safe Mode did no good, Onyx seems to work only on the system disk, so I've erased the TM volume and re-set TM to the same place. First Aid gives a clean bill of health, though it does take a while to do so. So that's great, thanks for the suggestions.

A utility that uses S.M.A.R.T. data provides a more comprehensive snapshot of drive health than Disk First Aid.  Of course, the drive/enclosure must be S.M.A.R.T. compatible.  . .

Tom_N Forum Pro • Posts: 18,544
Re: First Aid Failed.

lightandaprayer wrote:

ciaran33 wrote:

First Aid in Safe Mode did no good, Onyx seems to work only on the system disk, so I've erased the TM volume and re-set TM to the same place. First Aid gives a clean bill of health, though it does take a while to do so. So that's great, thanks for the suggestions.

A utility that uses S.M.A.R.T. data provides a more comprehensive snapshot of drive health than Disk First Aid. Of course, the drive/enclosure must be S.M.A.R.T. compatible. . .

S.M.A.R.T. data is concerned with monitoring the health of the hardware.  Disk First Aid is concerned with monitoring and repairing file system corruption and permissions settings.

If your drive fails (something that S.M.A.R.T. status may warn you about, in advance), you will lose non-backed-up data.  But if your file system is corrupt, that does not necessarily mean that the drive hardware is going bad.

lightandaprayer Senior Member • Posts: 4,001
Re: First Aid Failed.

Tom_N wrote:

lightandaprayer wrote:

ciaran33 wrote:

First Aid in Safe Mode did no good, Onyx seems to work only on the system disk, so I've erased the TM volume and re-set TM to the same place. First Aid gives a clean bill of health, though it does take a while to do so. So that's great, thanks for the suggestions.

A utility that uses S.M.A.R.T. data provides a more comprehensive snapshot of drive health than Disk First Aid. Of course, the drive/enclosure must be S.M.A.R.T. compatible. . .

S.M.A.R.T. data is concerned with monitoring the health of the hardware. Disk First Aid is concerned with monitoring and repairing file system corruption and permissions settings.

If your drive fails (something that S.M.A.R.T. status may warn you about, in advance), you will lose non-backed-up data. But if your file system is corrupt, that does not necessarily mean that the drive hardware is going bad.

Exactly right, which is why I suggested using a utility like DriveDX to monitor the mechanical fitness of drive and to have the ability to replace it before it fails (with the possible loss of data).

OP ciaran33 Contributing Member • Posts: 638
Re: First Aid Failed.

Is there a decent free equivalent to DriveDX ?

Also, I note that my system SSD drive is "S.M.A.R.T. status not supported" in Disk Utility. It is an SSD I put in place of the original HDD, if that matters. Thanks again.

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Tom_N Forum Pro • Posts: 18,544
Re: First Aid Failed.

ciaran33 wrote:

Is there a decent free equivalent to DriveDX ?

Also, I note that my system SSD drive is "S.M.A.R.T. status not supported" in Disk Utility. It is an SSD I put in place of the original HDD, if that matters. Thanks again.

My iMac still has its original HDD.  The S.M.A.R.T. status for it as "Verified".  It would seem that your SSD does not have internal drive health monitoring analogous to that for HDDs, or, that if it does, it does not make the information available in this form.

OP ciaran33 Contributing Member • Posts: 638
Re: First Aid Failed.

It's a Samsung Evo 850 250gb on sATA that has SMART, but Samsung's own diagnostics app Magician does seem seem to support Macs. Huh.

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Tom_N Forum Pro • Posts: 18,544
Re: First Aid Failed.

ciaran33 wrote:

It's a Samsung Evo 850 250gb on sATA that has SMART, but Samsung's own diagnostics app Magician does seem seem to support Macs. Huh.

I don't know whether Samsung was too lazy to write a Mac version of  "Magician", or if they figured that it wouldn't do much good.  USB and Firewire enclosures often do not pass S.M.A.R.T. status back to a computer, so external drives probably wouldn't report S.M.A.R.T. status.  Most recent Macs come without internal user-serviceable drive bays; thus Samsung may have figured that Mac customers would all be using external disks.

Samsung does claim that the 850 EVO supports S.M.A.R.T status.  So it is puzzling that Disk Utility can't read it from an internal 850 EVO SSD.

graybalanced Veteran Member • Posts: 6,887
Re: First Aid Failed.

Tom_N wrote:

I don't know whether Samsung was too lazy to write a Mac version of "Magician"

They are too lazy to.

I had to update the firmware on my 840 EVO, and while they had a downloadable Mac fix for it on their website, the way this “Mac” fix worked was: Use a third-party method to create a bootable CD or USB stick and put the fix software on it, and reboot into it. It rebooted into MS-DOS or some form of Unix, I can’t remember. Anyway, you used the command line to run the utility. So Mac-like!

Samsung only got away with that because Macs use Intel CPUs and could therefore boot up that way. When we move to Apple Silicon I wonder if Samsung will ever bother to let us fix their drives on Macs again.

Back to on topic, when a Time Machine backup fails built-in verification, I have usually had success fixing them with hdutil (or was it diskutil) or DiskWarrior. I have kept DiskWarrior updated all these years (not cheap) but it is increasingly difficult to justify the cost because on new Macs booting into APFS, DiskWarrior can’t do everything it once could. This is supposedly because Apple has not provided enough documentation for APFS.

DiskWarrior can still help with current Time Machine volumes because they are still based on HFS+. But I have read that starting in Big Sur, Time Machine will be able to use APFS for faster and more compact/efficient backups. That might mean the only tools that will work on them would be Apple’s own.

lightandaprayer Senior Member • Posts: 4,001
Drive DX Info

ciaran33 wrote:

Is there a decent free equivalent to DriveDX ?

Also, I note that my system SSD drive is "S.M.A.R.T. status not supported" in Disk Utility. It is an SSD I put in place of the original HDD, if that matters. Thanks again.

DriveDX currently costs $19.99 for a personal license, which is a steal as far as I am concerned. I have it installed on two Macs. I do not know of any free utility that provides Drive DX functionality. There is a free demo so you can test its compatibility with your drives.

My Samsung T3 USB 3 external SSD plugged into a 2018 Mac Mini (Mojave) provides full S.M.A.R.T. support. But a bug requires unplugging/plugging it in for the data to appear. Otherwise only basic data is available. The internal Apple SSD is fully compatible.

My wife's 2011 13" MacBook Pro (High Sierra) has an internal Samsung 850 EVO. DriveDX displays full S.M.A.R.T. monitoring data for the SSD.  I'm not using any Samsung software with either SSD.

My OWC Mercury Elite Pro enclosures do not support full S.M.A.R.T. monitoring. According to OWC tech support, only its dual Mercury Elite Pro enclosure is compatible. And it may depend on using the optional RAID software; OWC wasn't forthcoming regarding that potential issue.

OP ciaran33 Contributing Member • Posts: 638
Re: First Aid Failed.

It does seem that DriveDX is the best option, thanks.

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