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An error occurred while preparing the installation

I did a factory reset and now I have to reinstall MacOS Sierra but it keeps saying an error occurred while preparing the installation. I have last years MacBook 12 inChe's. I also did the thing where you to go utilities and sync your time with Apple's. What do I do now?

MacBook, macOS Sierra (10.12.6)

Posted on Nov 13, 2017 3:14 PM

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Posted on Nov 13, 2017 3:26 PM

Clean Install of El Capitan or Later on a Clean Disk


  1. Restart the computer. Immediately after the chime hold down the Command-Option-Rkeys until a globe appears.
  2. The Utility Menu will appear in from 5-20 minutes. Be patient.
  3. Select Disk Utility and click on the Continue button.
  4. When Disk Utility loads select the drive (usually, the out-dented entry) from the side list.
  5. Click on the Erase tab in Disk Utility's main window. A panel will drop down.
  6. Set the partition scheme to GUID.
  7. Set the Format type to Mac OS Extended (Journaled.)
  8. Click on the Apply button, then click on the Done button when it activates.
  9. Quit Disk Utility and return to the Utility Menu.
  10. Select Reinstall OS X and click on the Continue button.


This should install the version of OS X that was pre-installed when the computer was new.

3 replies
Question marked as Best reply

Nov 13, 2017 3:26 PM in response to BobRost

Clean Install of El Capitan or Later on a Clean Disk


  1. Restart the computer. Immediately after the chime hold down the Command-Option-Rkeys until a globe appears.
  2. The Utility Menu will appear in from 5-20 minutes. Be patient.
  3. Select Disk Utility and click on the Continue button.
  4. When Disk Utility loads select the drive (usually, the out-dented entry) from the side list.
  5. Click on the Erase tab in Disk Utility's main window. A panel will drop down.
  6. Set the partition scheme to GUID.
  7. Set the Format type to Mac OS Extended (Journaled.)
  8. Click on the Apply button, then click on the Done button when it activates.
  9. Quit Disk Utility and return to the Utility Menu.
  10. Select Reinstall OS X and click on the Continue button.


This should install the version of OS X that was pre-installed when the computer was new.

Nov 14, 2017 2:39 PM in response to Kappy

How do you resolve the "an error occurred while preparing the installation. Try running this application again."

I deleted and made back up data in my iCloud. I restarted the computer trying to reinstall Mac OS Sierra, but I kept getting an error saying "an error occurred while prep

I deleted my files, including MacOs High Sierra on Mclntosh HD after making back up in my iCloud. I restarted the computer trying to reinstall Mac OS Sierra instead of High Sierra, but I kept getting an error message saying "an error occurred while preparing the installation try running this application again." I put the current date on terminal to fix this issue, but I still kept getting the same error message, Please help!

An error occurred while preparing the installation

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