Q: When I select the MultiColor Separation Plug-In in Adobe Photoshop, I get an error message, that the currently selected RGB working space profile is not a valid profile. I checked my "Color Settings" in Photoshop, but everything looks fine. Why do I get this message?
A: The error message occurs when, in the "Color Settings" menu, the "Settings" dropdown is set to a predefined item. For example "Europe Prepress Defaults". To enable the MultiColor Plug-in, simply change the "Settings" dropdown to "Custom".
Do do so click on "Edit" > "ColorSettings" > "Settings". Change this dropdown to "Custom".
When changing to "Custom", the profiles from the previous settings are not be changed. There is no reason to modify any of the selected RGB and CMYK profiles. Just select "Custom" in the dropdown menu. That's it! After this, the MultiColor Plug-Ins will work fine.