Unable to reinstall macOS High Sierra on my iMac with "About -405 seconds remaining" error

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Level 1

6 points

Unable to reinstall macOS High Sierra on my iMac with "About -405 seconds remaining" error

Hi,

I’ve formatted a 2011 iMac, and now when I try to reinstall its iOS (Sierra) it keeps giving me an “about -405 seconds remaining” and then nothing happens. I’ve tried about 10 times and I’ve formatted the disk several times both in EX-FAT and Journaled and can’t get past this.

(I am connected to Wi-Fi)

Any help would be appreciated, I would even just like to restore it to its factory settings or an older iOS.

Thanks in advance!

[Re-Titled by Moderator]

iMac 21.5″, macOS 10.12

Posted on May 1, 2023 8:50 AM

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Answer 1

Jul 11, 2024 4:59 AM in response to PlumpWaif

PlumpWaif wrote:

factory reset this

Try Internet Recovery. With High Sierra you need to do this workaround in the Terminal (I hope Apple finally fixes this...):

https://mrmacintosh.com/how-to-fix-the-recovery-server-could-not-be-contacted-error-high-sierra-recovery-is-still-online-but-broken/

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Answer 2

Aug 16, 2023 1:31 PM in response to Gio_ar_t

I had the same problem with a 2012 Mac mini: I had erased the disk and tried to reinstall macOS from macOS Recovery, as described in this document: How to reinstall macOS – Apple Support (UK). I consistently got the “About -405 seconds remaining” error.

This is how I could solve it:

I used Shift-Option-Command-R during startup, which gave me the option to install Mac OS X 10.8 (Mountain Lion), this is the version of macOS that came with my Mac.
I then downloaded the disk image for the Mac OS I needed (macOS Sierra) and installed it from there.

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Answer 3

BDAqua

Level 10

250,181 points

May 1, 2023 9:05 AM in response to Gio_ar_t

EX-FAT will never work, may even stop a successive install attempt rom working. has to be MacOS Extended Journaled.

What has often worked for others is to use this Restore Method instead of CMD+r keys...

Option-⌘-R

Upgrade to the latest macOS compatible with your Mac.

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Answer 4

Jul 11, 2024 1:56 AM in response to Gio_ar_t

I tried this solution, and now instead of the apple logo appearing in the white background, there is a blinking file with a "?" on in. Please advise how this issue could be solved? I simply want to factory reset this. Thank you!

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