Imac 27 inch 2011 grey screen after boot

[UK2011mac]

Hi All
Just joined today to see if i could get some helpful info to get my Imac working again.
Brief outline of the problem.
I have an imac 27 inch 2011 model.Earlier in the week i was working on the mac and the mouse pointer froze.i thought it was just the batteries had died.i got up to get new batteries when the Imac switched off,it rebooted to a dark grey screen with a big error message in the middle in a smaller grey box.It said something along the lines of "closed due to an error" i didn't read the whole message or take down the error number.After a few minutes it booted back up,but now it only goes to a grey screen.
I have spent a couple of days googling and have tried unplugging all peripherals and rebooting that didn't work i have tried safe mode but it wont boot into safe mode i have tried Command, Option, P, and R and that didn't work.I have managed to used Command and S and that booted to the black screen and i typed fsck -fy and at first it said it had modified,so i ran it two more times and it came up with the ok message,so rebooted the imac and it still boots to the grey screen.
I have no idea what to do?
I don't think the progress bar gets right to the end before the grey screen.
I have the latest operating system for this model.
Any idea's?
I really need to get it working.
Thank you in advance.

 

[r6mile]

Sounds like your GPU is dead or dying. This can be replaced - there is a whole thread here about it - though you will need to be confident in opening up your iMac, as it's not an entirely risk free process. You will also need to flash the VBIOS.

 

[Juicy Box]

What are your specs?

Are you able to get into recovery mode or internet recovery mode?

It is probably one of the usual suspects, either the GPU or HDD or both.

If it is one of the usual suspects, you have one of the few iMacs that both the GPU and HDD are replaceable, so you always have that option.

 

[UK2011mac]

i believe it to be a mid 2011 3.4 GHz i7 with a 1tb drive and 16gb of ram AMD Radeon HD 6970M graphics with 1GB of shared memory.
not sure about internet recovery mode?
I have tried command r and that doesn't work i have tried option command p+r both of these just go to the grey screen.The only one that has done anything is command+s i got the black screen where i typed fsck -fy and then reboot at the end.at first it said it was modified then i ran it two more times and it said it was ok,so i rebooted and it started up and went to grey screen again.I know the hard drive is old and it wasn't sounding great and i can hear it working when the mac starts up

 

[Juicy Box]

Are you using a wired keyboard?

Have you tried doing Apple's built-in HW diagnostic test?

Press and hold "D" as soon as you press the power button and hear the chime.

It takes a while to boot up, but you should see some type of electronic icon (I can't remember what it looks like) to show that the HW diagnostic tool is booting.

Run the short test, and if it comes back as everything is fine, then run the extended test. The extended test could take a few hours.

Do this before internet recovery mode and let us know about the results.

I have had a few false negatives with Apple HW diagnostic, but I never had a false positive, so it can still be useful.

i believe it to be a mid 2011 3.4 GHz i7 with a 1tb drive and 16gb of ram AMD Radeon HD 6970M graphics with 1GB of shared memory.

That is discrete VRAM, not shared.

At the time of purchase, that was the second best GPU you could get for the Late 2009 to Mid 2011 iMacs.

But there does seem to be a high failure rate of GPUs on those models. Some speculate that it could be to the HDD running really hot and not enough cooling, causing the GPUs to deball or fry.

I have personally repaired (or reballed) the a 2GB AMD Radeon HD 6970M GPU by baking it in the oven. It has worked for a few years now, but some times they fail not too long after doing the oven bake.

Many people replace the fried cards with newer, better cards that are not officially support, but can work with that iMac.

But, lets not worry about that until you try other things.

not sure about internet recovery mode?

You can do this by pressing and holding command+alt/option+R at soon as you press the power button and hear the chime.

It can sometimes take a while to boot, but you will should see a spinning globe in about a minute, and it may take a few minutes to load the internet recover mode once you see the globe. Connecting to the internet using ethernet seems to speed up the process for me in the past.

You can then run first aid on your HDD using Disk Utility, and reinstall the OS if needed.

 

[UK2011mac]

Morning vertical smile
Thanks for your speedy reply.
I was using a wireless keyboard that came with the mac,but i also have a 2009 mac that i am using and i have paired the keyboard with that so not sure it will work on the troublesome mac.I have a wired mac keyboard that i am now using on that.
I have tried command+alt/option+R,so i press them as soon as i hear the chime? i am sure when i do it,that the mac just reboots and as long as i hold them it just reboots.so maybe i am doing something wrong.
The first thing i tried was removing all peripherals including ethernet cord which i have plugged into my other mac,should i reconnect it and try again?

 

[Juicy Box]

Do the hardware diagnostic tool first, just to see if there is something going on with the HW.

Press "D" after pressing power to start HW diagnostic.

The first thing i tried was removing all peripherals including ethernet cord which i have plugged into my other mac,should i reconnect it and try again?

Try it with ethernet plugged in.

You do it at the chime, or basically anytime once you hit the power button up to the chime, and maybe a few seconds after the chime, but you can never do it too soon.

If command+alt/option+R doesn't work, try holding the same, but add "shift" to the key presses.

 

[UK2011mac]

I just pressed D and got the starting internet recovery screen i was on wifi but just connected the ethernet cable.Been on the starting internet recovery screen for about 5 minutes....

 

[Juicy Box]

I just pressed D and got the starting internet recovery screen i was on wifi but just connected the ethernet cable.

WHAT?!?

You pressed "D" at start up and you are getting internet recovery?

"D" is for Apple's HW Diagnostic Test, not internet recovery mode.

Are you sure you are not in the HW Diagnostic Test?

Maybe start over, but make sure everything including the ethernet is unplugged except a wire keyboard and mouse.

Been on the starting internet recovery screen for about 5 minutes....

I am unsure what you mean by this. Are you given options? Maybe take a screenshot for us?


BTW, plug the ethernet cable back in for when you attempt to go into Internet Recovery Mode, but leave it unplugged for the Diagnostic Test.

 

[UK2011mac]

Ethernet unplugged only wired keyboard left plugged in.Started mac again,pressed D and it loaded with starting internet recovery screen and spinning globe and now it asks me to choose the wifi network

 

[UK2011mac]

Restarted it,Pressed and held D and it goes to the starting internet recovery screen and choose network like in the image i posted

 

[Juicy Box]

Restarted it,Pressed and held D and it goes to the starting internet recovery screen and choose network like in the image i posted

That is new to me. At least you know you can get into internet recovery.

Try pressing "option/alt" + "D" at start up, see if that works.

 

[UK2011mac]

Tried alt+d and got apple hardware test blue screen with grey box

 

[Juicy Box]

Tried alt+d and got apple hardware test blue screen with grey box

Are you able to run the test?

 

[UK2011mac]

i clicked it and it says testing.It said estimated time 3 minutes or longer depending on the amount of memory installed i have 16gb and the pass number is 1 and says the total time testing is 17 seconds,but its been 3-4 minutes,doesn't seem to be doing much

 

[Juicy Box]

says the total time testing is 17 seconds,but its been 3-4 minutes,doesn't seem to be doing much

This is completely normal

 

[UK2011mac]

its moving along now,sounds like its testing fans lol

 

[Juicy Box]

If there are no problems found using the short test, you can do the extended test.

But just a warning, that test could take hours to complete.

 

[UK2011mac]

6 mins 7 seconds test complete No trouble found it says

 

[Juicy Box]

6 mins 7 seconds test complete No trouble found it says

Well, you can try the extended test, or wait for that and use internet recovery and try to scan and repair your HDD.

The extended test can take a long while. I like to do that right before I go to bed when troubleshooting.

You might be able to fix your issue right away using internet recovery. If the HDD was corrupted, just reinstalling the OS could fix that, but if the HDD is failing, the issue might come back.

So, what would you like to do?

 

[UK2011mac]

Well being a part time photographer and having around 80,000 photos on that drive i would like to get into it.How do i do the long test?
Is there a way i can connect the drive to another mac to see if it works?
It seems that most of the keyboard shortcuts that maybe useful don't work.it wont go into safe mode command+alt/option+R when i click these it just goes to the grey screen no matter how long i press them,then it just reboots and does the same.I think the hard drive is fried it has been making noises for a little while,maybe it has just given up

 

[Juicy Box]

How do i do the long test?

IIRC, there is a little button to select, see the screen shot, it is in the read circle:

Is there a way i can connect the drive to another mac to see if it works?

If you are just trying to access the drive, there are a lot of options, especially if you have another Mac to use.

You need to connect your non-working iMac to another Mac, I need to know what Mac you plan on using to know the correct cable.

You need to use Target Disk Mode on your iMac. This turns your iMac into a huge external drive.

You do this by holding "T" during start up. There should be a little icon dancing on the screen showing that you are in Target Disk Mode.

You can connect that iMac to any other Mac, and access all the file or even boot from the iMac's internal drive.
You can also run Disk Utility from the working Mac and/or reinstall the OS.

This all assumes that your iMac's internal drive still works enough to get the data.

Well being a part time photographer and having around 80,000 photos on that drive i would like to get into it.

DO NOT FORMAT THE IMACS INTERNAL DRIVE OR DO A CLEAN INSTALL OF THE OS!

I really hope you have a back up. There is no guarantee that your internal HDD still works.

 

[UK2011mac]

I do think the HDD is dead.I just tried Option-Command-R after googling it and it says to do this if over the internet and i get spinning globe but it doesn't load recovery tool it just goes to apple loading screen as if booting up.I do notice that the progress bar only goes to three quarters then to a grey screen
My other mac is this
Mac (21.5-inch, Late 2009)

3.06 GHz Intel Core 2 Duo


12 GB 1067 MHz DDR3

 

[Juicy Box]

I would try Target Disk Mode. What Mac can you use with this?

I do think the HDD is dead.

HDDs typically don't just die, they usually have problems leading to a failure.

Actually, I have had HDDs that were failing for literal years.

it and it says to do this if over the internet and i get spinning globe but it doesn't load recovery tool it just goes to apple loading screen as if booting up.

I am not following. Are you saying that internet recovery mode doesn't fully load, and it just starts up normally?

I do notice that the progress bar only goes to three quarters then to a grey screen

This happens often with GPU failure, but I have also seen it happen with HDD failure.

 

[UK2011mac]

"I am not following. Are you saying that internet recovery mode doesn't fully load, and it just starts up normally?" Yes

I just tried "shift" to boot to safe and i now get three drives show up with arrows which didn't happen before.I click recovery and it just goes to grey boot screen (see image)
I also know the drive has been grinding for a few weeks on startup and it takes a while to stop and about 10 minutes before i can use mac properly so i defo think drive is the problem