Getting error code -128 on a late-2015 iMac [duplicate]

Question

Late 2015 iMac is rebooting on its own. Only Finder running, OSX 10.11.6. (2) 8GB RAM sticks. Got to catch it in the act today.

After reboot I find kernel: Previous shutdown cause: -128

That doesn't appear to correspond to anything useful in the old MacOS error codes documentation from 1998:

-128 userCanceledErr User canceled an operation

http://www.macwizard.com/errors.html

The is a refurb unit, hoping it doesn't need to go back for another refurbishment.

thanks

Answer 1

The precise meaning of the shutdown cause codes is not publicly documented, so linked error about userCanceledErr isn't correct, as these are different list of codes.

The shutdown cause -128 in general is related to the unknown hardware issue (e.g. RAM). If it happens repeatedly, you should take it to the repair.

See also:

• Shutdown Cause -128
• Are OS X shutdown cause and sleep cause numbers listed/explained anywhere?