This warning is displayed because of either of the following reasons:
1. Your MAC display is set to 256 colors. To resolve this, do the following:
- Open System Preferences located in your Applications folder
- Select "Displays" located in the "Hardware" section
- In the "Colors" field, select a color option of Thousands or Millions.
- Restart MATLAB. The warning message should not be displayed now.
2. Your X11 environment is set to 256 colors. To resolve this, do the following:
- Open X11 located in your Applications/Utilities folder
- Select X11 > Preferences from the top menu bar.
- Select "Output" from this menu
- In the "Colors" field, select a color option of Thousands or Millions.
- Quit X11 by selecting: X11 > Quit X11
- Restart MATLAB. The warning message should not be displayed now.
Best Answer