You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Problem with installing system

I formatted my MacBook a few hours ago. Everything was fine but then I deleted NVRAM or PRAM memory and I was only seeing blinking folder with a question mark. I restarted my MacBook, then clicked Command+R, also Shift+Option+Command+R and all of the recommendations from Apple site but when I’m installing macOS Sierra, I’m going to have this „An Error Occurred While Preparing the Installation. Try running this application again." I dunno what to do right now, because I can’t do anything with my computer...

MacBook Pro 15″, macOS 10.15

Posted on Jun 24, 2020 2:07 PM

Reply
Question marked as Top-ranking reply

Posted on Jun 24, 2020 2:14 PM

Repair a storage device in Disk Utility on Mac

Disk Utility can fix certain disk problems—for example, multiple apps quit unexpectedly, a file is corrupted, an external device doesn’t work properly, or your computer won’t start up. Disk Utility can’t detect or repair all problems that a disk may have.

If you run First Aid on a disk, Disk Utility checks the partition maps on the disk and performs some additional checks, and then checks each volume. If you run First Aid on a volume, Disk Utility verifies all the contents of that volume only.

  1. In the Disk Utility app  on your Mac, choose View > Show All Devices.
  2. Note: If you’re checking your startup disk or startup volume, restart your computer in macOS Recovery, select Disk Utility in the macOS Utilities window, then click Continue. If you check your startup volume (Macintosh HD), make sure you also check your data volume (Macintosh HD - Data).

  3. In the sidebar, select a disk or volume, then click the First Aid button .
  4. If Disk Utility tells you the disk is about to fail, back up your data and replace the disk—you can’t repair it. Otherwise, continue to the next step.
  5. Click Run, then click Continue.
  6. If Disk Utility reports that the disk appears to be OK or has been repaired, you’re done. You can click Show Details to see more information about the repairs. Otherwise, you may need to do one of the following.
    • If Disk Utility reports “overlapped extent allocation” errors, two or more files occupy the same space on your disk, and at least one of them is likely to be corrupted. You need to check each file in the list of affected files. Most of the files in the list have aliases in a DamagedFiles folder at the top level of your disk.
      • If you can replace a file or re-create it, delete it.
      • If it contains information you need, open it and examine its data to make sure it hasn’t been corrupted.
    • If Disk Utility can’t repair your disk, or you receive a report that the First Aid process failed, try to repair the disk or partition again. If that doesn’t work, back up as much of your data as possible, reformat the disk, reinstall macOS, then restore your backed-up data.

If your Mac has a Fusion Drive and you see a flashing question mark or alert, see the troubleshooting section of the Apple Support article About Fusion Drive, a storage option for some Mac computers.

If you continue to have problems with your disk or it can’t be repaired, it may be physically damaged and need to be replaced. For information about servicing your Mac, see Find out how to service or repair your Mac.


5 replies
Question marked as Top-ranking reply

Jun 24, 2020 2:14 PM in response to bartekmuller

Repair a storage device in Disk Utility on Mac

Disk Utility can fix certain disk problems—for example, multiple apps quit unexpectedly, a file is corrupted, an external device doesn’t work properly, or your computer won’t start up. Disk Utility can’t detect or repair all problems that a disk may have.

If you run First Aid on a disk, Disk Utility checks the partition maps on the disk and performs some additional checks, and then checks each volume. If you run First Aid on a volume, Disk Utility verifies all the contents of that volume only.

  1. In the Disk Utility app  on your Mac, choose View > Show All Devices.
  2. Note: If you’re checking your startup disk or startup volume, restart your computer in macOS Recovery, select Disk Utility in the macOS Utilities window, then click Continue. If you check your startup volume (Macintosh HD), make sure you also check your data volume (Macintosh HD - Data).

  3. In the sidebar, select a disk or volume, then click the First Aid button .
  4. If Disk Utility tells you the disk is about to fail, back up your data and replace the disk—you can’t repair it. Otherwise, continue to the next step.
  5. Click Run, then click Continue.
  6. If Disk Utility reports that the disk appears to be OK or has been repaired, you’re done. You can click Show Details to see more information about the repairs. Otherwise, you may need to do one of the following.
    • If Disk Utility reports “overlapped extent allocation” errors, two or more files occupy the same space on your disk, and at least one of them is likely to be corrupted. You need to check each file in the list of affected files. Most of the files in the list have aliases in a DamagedFiles folder at the top level of your disk.
      • If you can replace a file or re-create it, delete it.
      • If it contains information you need, open it and examine its data to make sure it hasn’t been corrupted.
    • If Disk Utility can’t repair your disk, or you receive a report that the First Aid process failed, try to repair the disk or partition again. If that doesn’t work, back up as much of your data as possible, reformat the disk, reinstall macOS, then restore your backed-up data.

If your Mac has a Fusion Drive and you see a flashing question mark or alert, see the troubleshooting section of the Apple Support article About Fusion Drive, a storage option for some Mac computers.

If you continue to have problems with your disk or it can’t be repaired, it may be physically damaged and need to be replaced. For information about servicing your Mac, see Find out how to service or repair your Mac.


Jun 24, 2020 2:48 PM in response to BDAqua

Unfortunetely, First aid doesn’t work - „Error process first aid. If possible, back up data from this volume. Click Ready to continue”. Sorry for any mistakes, I’m using polish language on my MacBook and translating this. So anyway, I don’t want to back up anything, because my disks are empty. Still I can’t do anything. Any ideas?

Problem with installing system

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.