If your MacBook is behaving as though it's possessed these days, you're not alone.  

There have been an ever increasing number of MacBook users who are reporting the problem as witnessed by the complaints on Apple's own support forum as well as other popular forums for Apple users.  

The issue appears to be related to the installation of the 10.11.4 operting system update and strangely seems to impact the MacBook Pro product line more so than other Mac products.  

The issue was first reported in the Mac Rumors forum for Apple users, and was recently highlighted in Fortune online.  

If you are experiencing the issue, the options for resolving it may not be what you want to hear.  In summary, you can

1) roll back to version 10.11.3 (if you happen to have a complete backup of your system with 10.11.3 installed; 2) hold down the power button until the system reboots (hard reboot) and live with the problem until 10.11.5 (currently in beta testing) is released.