Unibody MacBook Pro models with 13" displays produced from 2009-2012.

3946 Questions View all

Shutdown on disconnecting power adapter, restarts on reconnection.

My MacBook Pro has been experiencing a number of strange issues. As soon as its disconnected from the power adapter it shuts down. I've tried cleaning the contacts and checking the pins.

The machine will then not restart, even though the battery read 99% at the tie of shutdown, until the power adapter is reconnected, at which point it will restart automatically. Usually, but not always, it will show the Prohibitory Symbol. This will flicker to the Apple logo and then the machine will boot and load normally.

The magsafe adapter is stuck on green.

I've tried resetting the NVRAM and SMC. This boot issue coincides with these logs from the last command.

reboot    ~                         Sun Jan  1 00:02 
reboot    ~                         Thu May 18 17:31 
reboot    ~                         Sun Jan  1 00:00 
reboot    ~                         Thu May 18 17:11 
reboot    ~                         Thu May 18 16:59 
reboot    ~                         Sun Jan  1 00:00 
reboot    ~                         Thu May 18 16:45 
reboot    ~                         Thu May 18 16:38 
reboot    ~                         Sun Jan  1 00:00 
reboot    ~                         Sun Jan  1 00:00 
reboot    ~                         Sun Jan  1 00:00 
reboot    ~                         Thu May 18 14:04 
reboot    ~                         Sun Jan  1 00:00 
reboot    ~                         Tue May 16 10:05

All reboots prior to this are on normal time.

Battery information is as follows (I know its a really high cycle count, could this be the issue?)

Model Information:
  Serial Number:    W0402ZAL4D3LC
  Manufacturer:    SMP
  Device Name:    bq20z451
  Pack Lot Code:    0
  PCB Lot Code:    0
  Firmware Version:    201
  Hardware Revision:    000a
  Cell Revision:    165
  Charge Information:
  Charge Remaining (mAh):    4176
  Fully Charged:    Yes
  Charging:    No
  Full Charge Capacity (mAh):    4219
  Health Information:
  Cycle Count:    1050
  Condition:    Replace Now
  Battery Installed:    Yes
  Amperage (mA):    0
  Voltage (mV):    12444

Any insight or tips much appreciated!

Answer this question I have this problem too

Is this a good question?

Score 0
Add a comment

1 Answer

It says your battery needs to be replaced. And it should be as it has over 1000 cycles.

You can confirm this using coconut battery


What model macbook pro do you have so i can find you the proper guide and battery for it?

MacBook Pro 13" Unibody Mid 2012 Battery Replacement

How to replace it.

MacBook Pro 13" Unibody (Mid 2009-Mid 2012) Battery

There is the part.

1050 cycles is a lot. Most of these are supposed to last max of 1000

Was this answer helpful?

Score 0


Thanks for the speedy answer. Would a defective battery go from holding 4/5 hours to dead overnight? Also, would that type of shutdown (sudden loss of power) lead to the prohibitory symbol? As it appears for a good 45 seconds even on restart without disconnecting the adapter.

MB is: MacBook Pro (13-inch, Mid 2012)


yes they can. they can act weird sometimes.


Add a comment

Add your answer

Jack Fuller will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 0

Past 30 Days: 1

All Time: 46