MBP 2011 won't complete boot/endless restart, won't boot from external HDD either

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A H1 Author

Level 1

53 points

MBP 2011 won't complete boot/endless restart, won't boot from external HDD either

I have a MBP 2011 that is showing some bizzare behavior. here are the symptoms and what I have done so far--

MBP 2011 15" (not sure exactly which vintage), High Sierra, HFS+

symptom:

start booting, get past the Apple logo and loading OS, but during the grey screen between the apple Logo and the login screen, it shuts down and then reboots, and go into endless cycle of this
will boot into single-user mode
will not boot using external HDD (Sierra, Snow Leopard)
will go into Target Disk Mode - FW800 connection works
Apple Hardware Diagnostic does not find any problem

stuff done and results

reset SMC
reset PRAM
started on Target Disk Mode (via FW800), ran first aid. it corrected some Volume Metadata corruption, etc
ran DiskWarrior 5, rebuilt the directory, no corruption found other than the usual text encoding error
tried starting up in Safe Mode --> hangs after OS load (apple logo screen). after a loooong delay I gave up and forced shutdown
startup device option works (holding down opt during startup), so can select external drive to boot from
try to reboot using external drive. will go into endless reboot cycle, same as trying to boot from internal drive (this makes me suspect it's a hardware issue). tried booting into Sierra or Snow Leopard, to no avail
started up on single user mode. boots ok to get prompt, can run fsck and shows no issue with disk
passes built-in hardward diagnostics
pulled out DIMM.. it booted once, but after that, fail to complete bootup. so doesn't seem to be the known DIMM socket defect issue

currently I'm backing up the content of the HDD while I still have access to it via Target Disk Mode. I'm about to reformat the HDD to see if that would somehow miraculously fix something, but I doubt it given it won't boot into external HDD.

what else should I attempt to try to get this machine to work? or is this machine toast due to some weird hardware failure that hardware diagnostics can't detect? I could try booting using the original installer DVD after I'm done with the backup.. anything else?

MacBook Pro

Posted on Jan 6, 2019 11:49 AM

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Answer 1

Top-ranking reply

dwb

Level 7

33,268 points

Jan 6, 2019 2:38 PM in response to A H1

That you can boot another computer with this computers hard drive but this computer will not boot and assuming the external drive you also couldn’t boot with is a known good boot disk I’d suspect RAM. You say you pulled a DIMM - do you mean you reseated the RAM and it booted once or that you booted with just one DIMM? Assuming you have 2 DIMMs, I’d pull both and then try booting with just 1 in the lower slot, testing both DIMMs individually. Again, assuming you have RAM in both slots, I’d not expect both to go bad at the same time.

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Answer 2

DonH49

Level 6

16,716 points

Jan 6, 2019 2:57 PM in response to A H1

Especially if you still are using a platter internal hard drive, I'd pull it out and insert first an inexpensive SSD. A internal hard drive that is just wore out can cause this type of issue. Its more than 8 years old, I'd think give it a try.

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Answer 3

A H1 Author

Level 1

53 points

Jan 6, 2019 3:54 PM in response to dwb

Yes. I pulled one DIMM out and at one point it would boot. but now it won't with or without the second DIMM in the socket. I have another MBP2011 with a bad DIMM socket and is running on a single DIMM module, and that one, it gave me the hardware check failure buzzer sound upon startup. this one doesn't. So I don't think it's the DIMM/RAM error...

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Answer 4

A H1 Author

Level 1

53 points

Jan 6, 2019 4:14 PM in response to A H1

ok. I rebooted using verbose mode. It got to this screen, then it went to "blank grey screen" and then rebooted. it says "Unsupported CPU"

???

I took a screen shot right before it went to blank grey screen.

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Answer 5

A H1 Author

Level 1

53 points

Jan 6, 2019 3:58 PM in response to DonH49

if it's the internal HDD problem, I should be able to boot this machine using a known good external boot drive since it would bypass the bad HDD. but regardless of OS/external/internal HDD, it aborts boot sequence after the apple logo progress bar completes, but before showing the login screen. so I don't think it's the internal HDD itself. it could be bad cable, etc., so I suppose I can open it up and take a look at all the wiring to make sure it's seated.

I'm going to try booting again in verbose mode and see if I can catch wehre it hangs and crashes/reboots during the boot cycle. right now waiting for the backup to complete...

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MBP 2011 won't complete boot/endless restart, won't boot from external HDD either

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