Should this 27" iMac have an MS-DOS partition on it?

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Level 1

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Should this 27" iMac have an MS-DOS partition on it?

This is a refurbished iMac from the largest retailer in the world with a fresh install of Mac OS Monterey that was left alone without a password for a short time and (someone) was able to get a Mac wireless keyboard & trackpad connected to it, but that is a whole other issue. Or is it. This Mac which absolutely does not, nor ever did have anything to do with parallels or anything 'bootcamp' related shows a 209MB MS-DOS EFI partition and the rest of the 1TB drive has an APFS Volume. A lot can fit on that 209MB space. Is there any reason or is it even possible that this was created during the OS install?

iMac Line (2012 and Later)

Posted on Jul 4, 2022 2:49 AM

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Answer 1

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Allan Jones

Level 9

78,428 points

Jul 4, 2022 8:18 AM in response to mandell_liam

Without guessing, I confidently say "normal."

I have seen that on my Macs, which were all new directly from Apple, and in hundreds of drive reports from other Macs. The EFI partition is always shown formatted that way. It is likely a side-effect of Intel processors. The Wiki article below states that, prior to Macs using Intel processors (2006), the EFI had to be formatted HFS+, an Apple-only format. With intel processors it doesn't matter.

Its formatting does not show on my 2017 iMac with a factory blade SSD on the NMVExpress bus:

but does on my older MacBook Pro with an SATA drive bus:

as well as the three external USB mech backup drives attached to the iMac. Sample:

See:

https://themacadmin.com/2012/02/15/mounting-the-efi-boot-partition-on-mac-os-x/

Good article here: https://en.wikipedia.org/wiki/EFI_system_partition#Apple.E2.80.93Intel

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Answer 2

HWTech

Level 9

69,536 points

Jul 4, 2022 9:49 AM in response to mandell_liam

Macs have a UEFI firmware which uses an EFI (aka ESP) partition which is perfectly normal. The ESP partition is meant to hold the boot loader, but I don't believe Apple uses it much these days, although it is needed for booting a non-Apple OS on a UEFI Mac.

https://en.wikipedia.org/wiki/EFI_system_partition

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Answer 3

ku4hx

Level 7

23,694 points

Jul 4, 2022 3:33 AM in response to mandell_liam

My guess is it's a remnant of a previous users usage.

On a "clean" Mac, there is no Microsoft anything

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Should this 27" iMac have an MS-DOS partition on it?

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