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install mac os

I have tried a few times to install mac os sierra and the install reaches a few seconds before completing installation and I receive an error and ask me to run the application again, try again and same problem occurs

MacBook Pro 13″, macOS 11.0

Posted on Jun 10, 2021 2:52 AM

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Posted on Jun 10, 2021 6:17 PM

If you are downgrading from macOS Big Sur to macOS Sierra then you need to erase the disk correctly,

and reformat it from APFS to Mac OS Extended (Journaled)

Sierra does not run on APFS formatted disks.


Restart your mac to your Recovery HD.

Open Disk Utility, click on View in the menubar and select Show All Devices.


High light the Disk (Apple SSD.... or similar) not any of the indented Volumes.

Click Erase.

Give the Disk a name.

Format: Mac OS Extended (Journaled)

Scheme: GUID Partition Map.

Click Erase.


When Done quit Disk Utility.


Click on Reinstall OS.

4 replies
Question marked as Best reply

Jun 10, 2021 6:17 PM in response to macman1955

If you are downgrading from macOS Big Sur to macOS Sierra then you need to erase the disk correctly,

and reformat it from APFS to Mac OS Extended (Journaled)

Sierra does not run on APFS formatted disks.


Restart your mac to your Recovery HD.

Open Disk Utility, click on View in the menubar and select Show All Devices.


High light the Disk (Apple SSD.... or similar) not any of the indented Volumes.

Click Erase.

Give the Disk a name.

Format: Mac OS Extended (Journaled)

Scheme: GUID Partition Map.

Click Erase.


When Done quit Disk Utility.


Click on Reinstall OS.

install mac os

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