how to fix corrupted disk?

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how to fix corrupted disk?

iMac suddenly launching with "keychain" damage messages; restart after PRAM zapped, Apple apps now not working at all. Disk Utility online ran; no issues found.

I suspect some kind of corruption? Can;'t launch system prefs!

Tried to "manage" storage; won't load list of files....=0

Can still log in after shut down and restart; 3rd party apps as well won't open, may be "damaged or incomplete"...

Disk is almost full; deleted large desktop files in total; emptied trash.

whaaaaaaaaaaaaa? Never experienced this before. =(

Am I doomed to just do online restore?...?

Posted on Jan 25, 2022 10:38 AM

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Answer 1

Top-ranking reply

HWTech

Community+ 2026

Level 9

73,690 points

Jan 27, 2022 10:17 AM in response to gloriafromdearborn

You need to click on the "Fusion Drive" and erase it as GUID partition and MacOS Extended (Journaled). Then quit Disk Utility and select the "Reinstall macOS" option. From your picture it appears you were booted into macOS 10.12 or earlier. If you happen to be booted to a macOS 10.6 to 10.10 installer, then you may instead need to select the "Fusion Drive" and then in the "Partition" tab select "1 partition".

After you reinstall macOS, I highly recommend you run DriveDx to check the health of the internal SSD and hard drive. Post the report for the SSD and hard drive here using the "Additional Text" icon which looks like a piece of paper. You can also run the Apple Diagnostics to look for possible hardware issues, but unfortunately the diagnostics don't detect many types of drive failures like DriveDx does.

FYI, you should always have frequent and regular backups of your computer and any external media which contains important and unique data.

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Answer 2

DonH49

Level 6

16,726 points

Jan 25, 2022 11:26 AM in response to gloriafromdearborn

I view that type of corruption as a poor initial system install. No amount of reinstall is going to repair the damage. If you don't have any personal information to save then a good solid reinstall of the system is in order. That means to erase the drive first then do the install. BUT....if you present drive is APFS then instead of erase you should use the - button to delete the volume from the Container. Then use the + button to add a future volume back to the container. That way you will not get duplicate data volumes.

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Answer 3

Jan 28, 2022 4:24 PM in response to gloriafromdearborn

If you have a 2015 iMac, then you can actually install the most recent version of macOS which is macOS 12.x Monterey. Monterey still seems to have some growing pains as some users are still experiencing some compatibility issues with some USB3 drives and a few other issues. Some third party apps may not yet be fully compatible, so you should first check that any third party apps you have are compatible. You can find links to various macOS installers within this Apple article along with optional instructions for creating a bootable macOS USB installer:

How to create a bootable installer for macOS - Apple Support

Keep in mind beginning with macOS 10.15 Catalina, that macOS no longer supports 32 bit apps:

32-bit app compatibility with macOS High Sierra 10.13.4 and later - Apple Support

macOS has also been tightening security so you should make sure not to keep any files/folders on the root of the drive since that area will be locked read-only with macOS 10.15+:

About the read-only system volume in macOS Catalina - Apple Support

Since you are using Adobe products I would expect your iMac to have more than the usual amount of RAM (8GB) so any version of macOS should be fine to install taking into account the notes I have indicated here. I don't use any Adobe products and have very few third party apps installed and am not a macOS software expert.

Also, make sure to have frequent and regular backups of your computer and all external media which contains important & unique data.

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Answer 4

Jan 27, 2022 10:06 AM in response to DonH49

MEH!..just got my help from the lovely apple chat....I was worried about erasing the "HD" now named erroneously as OSx base; but all is good....don't we love apple. Can't kill 'em, can't leave em.....best support ever.

Now it's back, and the longwork of reinstalling 3rd party stuff.

Thanks

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Answer 5

Jan 25, 2022 11:41 AM in response to DonH49

Well, this is an "old'er (late 2015) 27" running Sierra 10.12.6; have never done any disk repair/reinstall ever.....=(

So it seems a "clean" install? Erase and then reinstall.....then go and reinstall 3rd party stuff...?

I must have telepathic connections; JUST backed up all important files in January....=0 before this nonsense....

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Answer 6

Jan 26, 2022 10:18 AM in response to gloriafromdearborn

Okay, so it's been years since I've had to do this kind of disk stuff! Years. So I'm clueless, here....=(

Since I "guessed" at which ("internal", or "external") drive to try to do a restore, I selected the MAC HD and apparently also wrongly chose to restore it from the OS X Base drive...=0. I'm just lost here. So I thought, okay, lets just try to reinstall High Sierra....to that now OS X base drive. I know, I know. Beyond words. This is an older Mac, so those "container"s and plus and minus stuff just aint' there in my Disk Utility windows. At this point I had 2 externals showing!. So I wondered if I tried to boot with option/command/R error code Disk Utility would have those options described..... -I got the dreaded exclamation point, "apple support.com", error code -5101F. Shut down. DID the plain old commandR boot, and it came up...here's this screen shot from Disk Utility. I'm lost and clueless, clearly. The only option to erase is now the "internal" base, will I blow up my machine (kidding, but not)...if I choose to erase it and then try to reinstall?.....never ever ever ever ever have I had this kind of craziness....ever ever ever....and I'm more than rusty. I've looked online for whatever info I can, and I'm sure it's out there, but I can't find. I SO appreciatte any help, including a "Mac in the 21st centruy for Dummies" book....=0

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Answer 7

Jan 27, 2022 11:35 AM in response to HWTech

thanks for this; I'll check out DRIVE DX. I'm just an old fashioned girl trying to live simply with as little interaction outside the apple bioisphere as possible....! This all is the first time I've EVER had any corruption with home system in over 30 years....oh well.

Lesson learned. I had a premonition things were on the brink, and fortunately backed up all last month on new LaCie....because I've never been unable to easily fix. Time to change plans....I appreciatte it.

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Answer 8

Jan 28, 2022 10:57 AM in response to HWTech

thanks again. Did the DriveDX, and all is perfect. Also used disk utility tdo check my 6 Lacie externals, all is well...thank goodness.

So I'm back on this late 2015 imac with Sierra, as I was using (preferred) my last Photoshop (6), and Lightroom stand alone. Adobe informs me I can no longer install these....(!!!)....wow, am I behind. I've been putting off using the "cloud" from Adobe for a LOT of reasons....but I do own the current versions of both. (And my Wacom will also be extinct with a new imac purchase.....)

which is on the close horizon. Meanwhile.....

Do you know what OS I should update to on the iMac to work best with them? Theres been so much out there with compatibility and OS updates.....I need no further problems!

I've seen I can update all the way to Big Sur; but this IS an older imac, and I don't want to tax the old girl unnecessarily!

Tried to post this; but not sure it was worded/directed to right place....

SO hard to get any info/help from Adobe has been my experience.....=(

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how to fix corrupted disk?

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