Virtual machine image is black in multimonitor Full Screen after the upgrade to Parallels Desktop 12 for Mac and above

Issue

• I have upgraded Parallels Desktop for Mac, and now my virtual machine's display image is black on an external monitor in Full-Screen.

Cause

Starting from version 12, Parallels Desktop for Mac supports only native macOS Full-Screen mode. After the upgrade, your virtual machine is now using the native macOS full-screen mode.

Any other application on a Mac will behave the same way: after entering the full-screen with the external monitor attached, the image on the external display will be black. This is a native macOS behavior, see the below discussions for more details:

• Dual monitors and fullscreen fiasco, is there a workaround?
• Why does Mac OS X turn off monitor #2 when an application is maximized on monitor #1?

Solution

1. Go to Apple logo > System Preferences > Mission Control.

2. Enable Displays have separate Spaces option.

   

3. Log out from a Mac user account and log in back.

4. Enter Full-Screen view mode with your virtual machine. To extend virtual machine to the external display go to View menu of the virtual machine > Use All Displays in Full Screen