I have a MacBook Pro 15" (Early 2011) model which suddenly is not booting correctly.
- Apple logo and loading bar appear.
- Loading bar loads part way, freezes for a while.
- Screen flashes momentarily, then grey screen appears.
- Grey screen stays forever.
Safe mode: symptoms unchanged
Single-user mode: symptoms unchanged
Verbose mode: symptoms unchanged
Clear NVRAM: Apple logo and loading bar appears, freezes, and stays that way forever. After another reboot returns to original behavior.
Boot from USB memory (with MacOS Sierra install): boot menu appears, and allows me to select the USB memory stick for booting, after starting boot process from memory, returns to original behavior (note that I used same memory stick to load MacOS Sierra onto a Mac Mini with no problems)
Removed Hard Drive completely (and attempted to boot from USB memory): symptoms unchanged
Replaced internal memory: symptoms unchanged
Attempted boot with charger unplugged: symptoms unchanged
So, I'm thinking that, if it is not the
- Hard drive, or
- Memory, or
- Power Supply
...then it must be the motherboard that is bad. Before I make that definitive conclusion, I'm wondering if there are any other ideas that I might try?
On a side note that might be more relevant than I think, I noticed that this model is one of the models potentially implicated in the MacBook solder scandal (see https://www.apple.com/support/macbookpro-videoissues/ which lists the 15" Early 2011 model as one of the model lines with problems). The symptoms don't exactly match what is listed there. I haven't noticed any video problems (except for when I was changing out the memory: I got a couple of strange all-blue screens, but that could just be a result of poorly seated memory). However, is it possible that a failing video adapter could cause problems at boot time?