If your default Photoshop settings are not standard, you may get the message, "Command "Invert" is not available" when trying to run some of our scripts that involve that command.
To stop this from happening and allow our scripts to run correctly, you need to change some default layer mask settings.
There are two places where this can be fixed.
Option 1: Options in Layers Palette
Click the icon in the top-right corner of the Layers Palette and select Panel Options.
In the Panel Options dialog box, make sure the "Use Default Masks On Fill Layers" box is checked.
Option 2: Options in Layers Palette
Select the background layer in your PSD, then click the Adjustments Palette Menu icon. Make sure the "Add Mask by Default" option is checked.