Early 2011 model, A1278 / 2.3 GHz i5 or 2.7 GHz i7 processor.

681 Questions View all

HDD Not Detected In Disk Utility With Current RAM

Earlier this week during use applications became locking up and slowly started force closing. Once things had completely locked up I held the power down and restarted the laptop. Startup only booted to the blinking question mark so I connected my external boot of 10.8 and looked at disk utilities and the HDD was no longer listed. After trying a drive I knew worked (which also wouldn't boot or display in disk utilities) I removed and replaced both DIMMS of RAM. This allowed me to boot. I ran memtest on the previous RAM several times now and it does not come up with any problems and when I boot into the external 10.8 image it sees the RAM perfectly but not the HDD. Any ideas what might be the case it would see the original RAM but not the HDD and in the second case see the HDD and the lower capacity RAM?


Model Name: MacBook Pro

Model Identifier: MacBookPro8,1

Processor Name: Intel Core i5

Processor Speed: 2.3 GHz

Memory: 16 GB

Boot ROM Version: MBP81.0047.B27

SMC Version (system): 1.68f99

Memory Slots:

ECC: Disabled


Size: 8 GB

Type: DDR3

Speed: 1333 MHz

Status: OK

Manufacturer: 0x8502

Part Number: 0x505341333847313333333253000000000000

Serial Number: 0x00000000


Size: 8 GB

Type: DDR3

Speed: 1333 MHz

Status: OK

Manufacturer: 0x8502

Part Number: 0x505341333847313333333253000000000000

Serial Number: 0x00000000

Answered! View the answer I have this problem too

Is this a good question?

Score 0
Add a comment

1 Answer

Chosen Solution

I think you created a second problem when you changed the RAM modules. As you stated the HD and your second HD still wouldn't show up under disk utilities.

Given the symptom of the locking up I suspect your HD is failing. Do you have access to a second Mac system running the same version of OS-X and a FireWire cable? If you do I would put your troubled MacBook into Target mode and then connect it to your other Mac. Then try running Disk Utility on it that way. If you still can't see it you'll need to take the Hard Drive out of your system and mount it to an external case (FireWire besting best) or use a SATA to USB adapter cable. Then try your other Mac again. If you still can't access it that way its to far gone. Time for a new Hard Drive.

Was this answer helpful?

Score 3


But when I change the RAM modules from the originals to a second set the drives show up in disk utilities. Which is strange the the drive showing up would be linked to what RAM is installed which explains my confusion. I guess a little more clear expression of the setups would be as follows.

Original setup:

Drive A and 2x8gb RAM modules.

Drive A doesn't display in disk utilities and both modules pass memtest 4 cycle testing and both modules display in system information. I also tested putting each module in separately and in each memory slot individually and still will not find the drive with either modules.

Second test:

Drive B and 2x8gb RAM modules.

Drive B doesn't display in disk utilities didn't test the RAM.

Third test:

Drive A and 2x4gb RAM modules.

Everything boots as normal. Drive A loads fine.

I hope this explains a little more clearly.


Any luck with a second Mac to access your systems HD via Target Mode? I would still try that. The only thing both your RAM & HD interconnect is the North Bridge I/O chip. But even still your symptoms are very odd. Changing out your memory shouldn't effect your HD access. I could see bad RAM crashing out the OS or App not having devices not showing up within the App.


Unfortunately I do not have a second Mac available to me at this time. If I do get the chance I will give it a shot. I'll ask around my friends if they have access to one I could borrow. Thank you for the responses.


It is possible that the hard drive cable is failing. It is a known weakness in 2011 (and previous) MacBooks. (I had to replace mine few months ago.) Such cable may behave strange – just opening/closing the bottom case can change the visibility of the internal hard drive. But if your test show consistent behaviour with given set of hardware, it might not be the case...


Add a comment

Add your answer

Patrick Hunter will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 0

Past 30 Days: 2

All Time: 492