2 MacBook shutdowns during boot up, with an unusual problem and fix.
My Macbook Air 13 (early 2014) started rebooting during startup with no apparent pattern. I was able to complete a login just once.
- SMC reset, PRAM reset had no effect.
- Re-seating SSD had no effect.
I suspected a logic board or RAM failure as there was no pattern to the reboots.
Came across a post on another forum where the user described a keyboard failure on their Pro. They were also unable to use any of the startup key sequences to boot from an external drive or run hardware diagnostics. Their fix was to replace the keyboard.
I decided to clean the keyboard by rubbing every key in all four directions.
Whatever was choking the keyboard got reset or dislodged and the system booted up as normal. It seems a stuck key can overload the keyboard microcontroller and trigger a crash/reboot.
Leaving this out here in case someone else has this strange problem.
I would plug in a USB keyboard to get around the internal keyboard issue. Once you do see if you can get into the onboard diagnostics pressing the D key.
Reference: Mac startup key combinations
Did you get a error? What was it
Dan さんによる
Hi Dan,
I did try all the key combinations using both the internal and an external keyboard.
There were no errors reported, the machine would shutdown at random points in the boot/single user/hardware diagnostics sequence.
As I said in my post, it turned out one key or more were stuck and triggering the crashes.
Vigorously cleaning the keyboard seems to have released the stuck key(s) and fixed the machine.
I’ve never seen an issue like this so I thought it might be useful to post this in case someone else runs into a similar problem.
I was worried it was a logic board or RAM failure, turned out to be just a stuck key.
Sanjay Mehta さんによる