Flashing question mark at startup

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wagnair Author

Level 1

4 points

Flashing question mark at startup

iMac 24", model A1225 (iMac 9.1), January 2009

500 GB HDD (not original) reformatted GUID, probably SSD

RAM : 2x4 Gb : not original

Wired Ethernet connection in order

Target mode boot on my MBP / High Sierra : HD visible, formatable, readable, writable

Boot via Cmd+R : Flashing question mark

Boot via Cmd+Alt+R : Flashing question mark

Boot via Shift+Cmd+Alt+R : Flashing question mark

Start via D (hardware diag) : Flashing question mark

Booting via Opt+D (online hardware diag) : Flashing question mark

Installing an OS 10.11.6 (dmg saved on the HD of the iMac and opened via MBP) : impossible --> no OS present

Recovery Disk Assistant : impossible --> no OS present

PRAM : zapped

SMC : reinitalized

No corresponding Time Machine available.

I tried to start with the TM of my Mac Mini / High Sierra : the TM is seen but it stops there. The question mark comes back (which seems normal to me : OS not supported)

How can I get this computer back up and running?

Thanks in advance...

Sergio

Posted on Jan 22, 2023 8:39 AM

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Answer 1

Best reply

D.I. Johnson

Level 7

22,409 points

Jan 22, 2023 8:58 AM in response to wagnair

The flashing question mark indicates that the Mac cannot locate an installed OS. Your startup drive may have become corrupted or is physically failing.

Please see: If your Mac doesn't start up all the way - Apple Support

You'll need to reinstall the macOS for your machine.

Please see: How to reinstall macOS - Apple Support

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Answer 2

Tesserax

Level 10

149,367 points

Jan 22, 2023 9:13 AM in response to wagnair

A flashing question mark would indicate a potential issue with your iMac's startup drive ... or that it does not contain a working version of OS X.

Since you tried starting up this Mac in Recovery Mode, and it failed to do so, the recovery partition on the system drive may be damaged or missing. Again, a failed drive would be the culprit. For reference, this particular iMac model came with either a 640 GB or 1 TB HDD.

Also <D> will not bring up the Apple Hardware Test on Macs prior to the 2010 models.

Do you happen to have the original (or copy) of the installation discs that came with this desktop? If so, you may be able to boot up the Mac with these ... assuming, of course, the optical drive is still functional.

Ref:

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Answer 3

wagnair Author

Level 1

4 points

Feb 12, 2023 11:40 AM in response to Tesserax

Here is the solution. Translation with the help of Deepl...

Creating a bootable key and downloading the OS 10.11.6 from the Apple site

As it is common, the message Unable to verify this copy of Install OS X El Capitan. It may have been damaged or altered during the installation. was displayed.

So I have changed the date of the Mac via Terminal. The command : date 093020002019 worked. It is likely that the one for the new certificates would work : date 102420002019

The updates have been done, the iMac is going on again !

Sergio

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