Hi guys,

I know this isn't a mac support forum. But I use this forum all the time and my mac is only used for music technology so I thought I would throw this out there in the hope that some of you might be able to shed some light on a problem for me.

I'm using a mac mid 2009 I bought in LA and bought back to the UK.
I put a new Momentus XT 750GB hybrid drive in 2 weeks ago because I was getting fed up of having all my audio files on an external drive. Everything was great I upgraded to lion and the drive was performing great.
Then it crashed and I got the question mark. ? Which has been the symbol of my life for the past 6 days

So I did some tests and my internal hardrive will boot from an external closure I have via USB
And the old harddrive I had before will also boot from the external closure via USB

I have reset the Pram
I have replaced the sata cable inside

Now I am stuck! I don't know what else to try. Hardrives work fine when booting via USB, but as soon as I stick either of them inside the mac. I get question mark

Please help shed any light on this, I have done many google searches across forums and can't find a solution
Desperately need my mac back. Please help if you know any ideas I can try

Can you run Disk Utility or Disk Warrior on the offending drive? You might need to boot to your OSX install disks, and then run Disk Utility from there.

If you have two USB enclosures, boot from the old hardware, and run tests on the current drive to make sure it's working. Then I'd probably back up the drive causing problems (for safety) and reinstall OSX to replace any missing or corrupted system files, and see whether that works.

Very odd that the drive will boot externally, and not internally. One other thing I'd try is to install a plain OSX setup on an empty drive and see whether that will boot from internally, to rule out any hardware problems.

Also, you could try running the Apple Hardware test as well, seeing if that throws up anything.

Hi recordplay

Desmond (as always has got there first) but just to add a little info, I can think of 3 possible causes:-

1/ Correct Boot needs to be set in system prefs.

Press 'Alt' when booting and select correct drive / partition (if it works go to Startup in system preference and select the correct drive for future startup)


2/ Cable not connected fully internally

3/ Hard Disk controller has gone to meet its maker

These two will be harder to diagnose but first base will be:-
a/ With the drive connected internally, boot to another drive / device (USB / OS disk)first run Disk utility and see if any internal drives are showing.
b/ Run System Profiler and see if it lists any devices under Serial-ATA or Run the diagnostic tests from an apple OS install CD/DVD.

Hope this helps

trouble shooting steps, depending on the computer you have: (is it a macbook pro?)

1. Boot using command V (verbose mode) this will give a detailed description of what is going on during the boot, it will also force the computer to run FSCK (basically the disk utility in command line) keep an eye out for "disk i/o error" this indicates a drive failure.

It may also attempt a repair on the data on the drive if it detects a problem, if possible, and let you know if it is successful or not, just like the disk utility took would. In command line, the disk utility has a slightly better chance of recovering the organisation of data on the drive.

2. try booting with your old hard drive, does it still boot? if not then the cable connecting the logic board to the hard drive could be faulty (most likely from your testing so far) , or worst case, the controller failing on the mlb (highly unlikely)

If it boots fine, it's your new HDD (a drive is most likely to fail when new, or very old, so not uncommon)

3. have you replaced your ram, bad ram can cause errors on data stored on the drive, this can cause problems if a boot file becomes corrupted during a background edit to a preference etc.

4. There is the possibility of the optical drive interfering with the SATA bus if it has a fault, easy to test. Disconnect the CD drive and try booting.

Thank you guys (and especially TBTS) Some really useful tips and diagnostics. I used all of these and just thought I would report back with results in case someone else has a similar problem. (I have a Mid 2009 Mac Book Pro BTW)

I Replaced the sata cable which I'm unsure was actually the problem now as my drives still didn't boot at all when replaced. I was baffled I could see the drive and spare drive but they still wouldn't boot (unless in an external USB enclosure)

What fixed it in the end was believe it or not, borrowing a snow leopard disk and booting from there onto a cleanly formatted drive. I have no idea why my bootable USB stick or bootable hardrive wouldn't let me do this (the drives would never show up this way). But anyway all sorted now. Clean install of snow leopard and then upgraded to Lion. Everything is fine (Crosses fingers)

Thanks for your help!

Sounds like the bus was stalled due to trying to work out the file system on your (bad) HDD, it will always check drives on the internal bus and then search on the external bus afterwards, so given enough time on boot manager it probably would find your USB partition, but it could take hours.

Glad it's all sorted now



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Apple Certified Technician. One half of http://www.turnbacktospring.com