Visual artifacts when moving Windows application window in Coherence

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My Windows virtual machine (VM) is running in Coherence view mode on Retina display (or external display). Retina view mode is set to Scaled. When I move the application window on the screen I see visual artifacts which feels like low Windows performance.


Running Windows VM on Retina in Scaled view mode requires an excessive amount of video memory.


  1. Exit Coherence.
  2. Suspend the virtual machine.
  3. Quit Parallels Desktop.
  4. Open and execute (copy-paste the entire command):

    defaults write "com.parallels.Parallels Desktop" "Application preferences.CoherenceOsScaling" 1
  5. Start Parallels Desktop, resume the VM and enter Coherence.

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