Help with El Capitan fresh install (black screen)

[Grasbak]

i am trying to help a friend clean install his 2008 imac with el captian.

He had upgraded to el capitan a while ago, but for a while now he could only boot in safe mode.

As I have performed a number of fresh installs on other machines, so I thought "no problem". I created a bootable usb with el captian on. Booted up with it, wiped the hard disk, then ran the installation. Seemed to run ok, but when complete it just hangs on a black screen - can't see a mouse cursor. Tried twice, same result.

Any ideas?

Only other thing i noticed was when i booted up with the USB, the screen had grey circles on it (in the background, large, like a ripple in water), wondered if that signified anything?

 

[Fishrrman]

Hard drive failure?
Graphics failure?

Do you have an EXERNAL drive that's bootable to the finder, that you could connect to his Mac?
If not, can you create one?

You want to see if you can boot his iMac "externally" (i.e., not using the internal drive at all), and "get to the finder" without problems.

That will rule out any other hardware problems.

Another path that might work:
1. Install a clean copy of El Cap to an EXTERNAL DRIVE
2. Use CarbonCopyCloner to clone that "fresh install" to the iMac's internal hard drive...

 

[Grasbak]

interestingly it will boot in safe mode.....

 

[Fishrrman]

Are you sure that you're actually booting into "safe mode" (this should "get you to the finder") and NOT into recovery mode (which gets you to the installer, disk utility, etc.)?

IF it will boot into safe mode -- but NOT "boot into his regular account" -- what that suggests to me is this:

- Mac is ok, hardware-wise (other than the hard drive).
- Hard drive is probably ok, hardware wise (because it boots into safe mode)
- Basic OS install is ok (again, it boots into safe mode).

These things can be a pain to diagnose.

SOMETHING TO TRY:
This "won't hurt anything", and can be easily removed later on.

1. Boot up in safe mode and log in.
2. Open the users & groups preference pane.
3. Choose to create a NEW account. MAKE SURE you give it administrative privileges.
4. Now, log out of the existing account and INTO the "new" account.
5. This will now be your "test account" (can be deleted later)
6. Shut down, reboot, and see if you can "get to" the new account without problems.
7. Can you do this?

 

[Grasbak]

firstly - thanks for helping

I can boot into safe mode. Tried the above, boot gets stuck just under 1/2 way through.

(I had wiped the hard drive and re-installed El Capitan)

Just trying to boot from my old El Capitan "superduper" back up. slow going as usb2. this seems to have stopped about a 1/4 through the boot process....

 

[Fishrrman]

If you can't boot from an external drive that YOU KNOW IS BOOTABLE, my guess is that some other hardware (other than the drive) has failed inside.

It could be video-related.

I'd tell your friend that it's probably time to be shopping for a new Mac...

 

[Grasbak]

can't say for sure it is bootable - it was set up that way in super duper but never had cause to check it. So am working to the assumption it would.

have been trying to run diagnostics, but can't seem to get it to run. holding down d on startup doesn't work. oh wait - using original discs its running
[doublepost=1519504319][/doublepost]short hardware test said no issue

 

[Grasbak]

long hardware test said no issue

 

[Grasbak]

tried installing El Capitan from fresh again - same result. Boots to a black screen, but you can boot into safe mode.

 

[Fishrrman]

Well... at this point... I'd try a DIFFERENT version of the OS.

You wrote above:
"oh wait - using original discs its running"

What are "the original discs"?
Are you referring to the install DVDs that came with it?

If they work -- when nothing else does -- why don't you try reinstalling [the original] OS from them?

When one method works and another doesn't -- use the method THAT WORKS...

 

[Grasbak]

i have the original discs that came with the iMac, and a snow leopard dvd

when using the original discs or snow leopard, i boot up holding c or shift - they all end up at black screen

 

[Fishrrman]

If nothing works... as I mentioned in reply 6 above... perhaps it's time for your friend to start looking for a replacement...

 

[Grasbak]

yep - looks that way. thanks again for the help.

 

[Grasbak]

one last question - when first wiped the hard drive i formatted at the top level in disk utility rather than the 2nd level (if that makes sense). Would that have caused any issue?