clean wipe

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Level 1

13 points

clean wipe

I want to erase everything no my mac yosemite. All encrypted data and all partition drives. Everything. Just like it was brand new. Then i want to install the latest updates (High Sierra) and all the apps . How do I do this? Yosemite 10.10.5  

Model Name: iMac

Model Identifier: iMac15,1

Processor Name: Intel Core i5

Processor Speed: 3.5 GHz

Number of Processors: 1

Total Number of Cores: 4

L2 Cache (per Core): 256 KB

L3 Cache: 6 MB

Memory: 8 GB

I was having problems earlier and I called Apple support and he tried to talk me through erasing the HD. I was left with some kind of partition I can't unmount even with the revertible command. How do I start from scratch?

Thanks 

iMac with Retina 5K display, OS X Yosemite (10.10.5)

Posted on Dec 11, 2017 2:34 PM

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Answer 1

Kappy

Level 10

361,741 points

Dec 11, 2017 2:48 PM in response to Opaque540

This is what you should do. You could also read What to do before you sell or give away your Mac.

Clean Install of El Capitan or Later on a Clean Disk

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

This should install the version of OS X that was currently installed. To install the original factory version when the computer was new use Command-Option-Shift-R.

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Answer 2

Opaque540 Author

Level 1

13 points

Dec 13, 2017 12:35 PM in response to Kappy

Select Reinstall OS X and click on the Continue button. This should install the version of OS X that was currently installed. To install the original factory version when the computer was new use Command-Option-Shift-R. Thx for this advice but in what order should I proceed with this last step to install the original factory version. Should I select Reinstall OS X, click on the Continue button then press Command-Option-Shift-R or press Command-Option-Shift-R first then select Reinstall OS X and click on the Continue button.

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Answer 3

Kappy

Level 10

361,741 points

Dec 14, 2017 11:47 AM in response to Opaque540

Which do you want to be installed? If you restart with Command-Option-Rkeys, then you will end up installing the version you had installed. If you restart with Command-Option-Shift-R keys, then you will end up installing the version that came pre-installed new from the factory.

If you are planning to give or sell the computer to someone then use the latter: Command-Option-Shift-R.

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