Error "Command "invert” at step _ is currently unavailable."
Please go to Window > Adjustments. You'll need to make sure it's in list view, then click on the little button at the top right of the palette. In the menu that appears, click on 'Add Mask by Default' and make sure there is a check mark next to it. Now, try running the action again. It's a default setting that should already be turned and on may not be for some reason.