MacBook Air frequent shutdown with shutdown with shutdown cause -128 I have an early 2015 13inch MacBook Air. 

Initially, One day after putting my computer to sleep, the display didn't turn on and there was no sign of computer working. Pressing power button also didn't work but it was charging when I attached the magsafe connector. 

So I left it alone for a few hours and started it again, it turned on. 

After this incident Im having frequent shutdowns with the shutdown cause -128. Sometimes while working on it and sometimes while waking up from sleep. 

I have reset the SMC, ran Apple Hardware check, EtreCheck app. No issues found. 

How can I troubleshoot this?
From our own George Garside's blog


  -128 --  Possibly linked to memory issue. If the issue is persistent, try replacing the RAM with known-good if your hardware has removable
  RAM.