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clean install macos catalina

Hi I need to do a clean install of macos catalina ...as my mac is running really slow ..even as i am writing this the multi coloured wheel keeps appearing ...so annoying !

so I followed instructions online ...went to "recovery HD' which suggested using "disk utility" and erase the HD and select "format type" Mac Os Extended ( Journaled) it does not show up

all i've got is : APFS

APFS (ENCRYPTED)

APFS (CASE SENSITIVE)

APFS (CASE SENSITIVE ENCRYPTED)

no Mac Os Extended ( Journaled)

could someone instruct me step by step what i need to do to m,ake a clean install of the existing macos catalina

thank you

iMac 21.5″, macOS 10.15

Posted on Nov 5, 2020 6:31 AM

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Question marked as Top-ranking reply

Posted on Nov 5, 2020 6:42 AM

You need to erase the disk, not the Volume.

However, APFS should be fine for Catalina.


In Disk Utility, click the View button and select Show all devices. Select the device and erase it.


Do you have a backup you plan to migrate from after erasing the drive?


Maybe you should check to see that you have installed something that is causing the problem. Erasing it and reinstalling the OS will remove that thing, but it might be simpler to just remove the thing.

Run Etrecheck and post the report here, in the Additional Text area (document icon in a reply window).

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2 replies
Question marked as Top-ranking reply

Nov 5, 2020 6:42 AM in response to Novice2011

You need to erase the disk, not the Volume.

However, APFS should be fine for Catalina.


In Disk Utility, click the View button and select Show all devices. Select the device and erase it.


Do you have a backup you plan to migrate from after erasing the drive?


Maybe you should check to see that you have installed something that is causing the problem. Erasing it and reinstalling the OS will remove that thing, but it might be simpler to just remove the thing.

Run Etrecheck and post the report here, in the Additional Text area (document icon in a reply window).

clean install macos catalina

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