What is the meaning of this Nik error message, please?

Suddenly, when I click on any of the Nik Collection plugins, I get error messages. If I have an image open in Photoshop and click to open Color Efex Pro 4, I get the message attached below. Similarly, if I attempt to open Viveza 2, I get the message "The command 'Viveza 2' is not currently available."

I'm working in Photoshop CS6 13.0.6 and have changed nothing in my preferences or computer setup that would account for this.

What does this mean, and how do I fix it?

Help!

It sounds like PS cannot find the NIK plugins. Try reinstalling them.

Thank you. At your suggestion, I reinstalled it but with no effect.

I've since found the answer, which is that the plug-in works only in the RGB color space and not on a CMYK or grayscale image. I'd converted the image to grayscale in Camera Raw—something I've almost never done before—then opened it in Photoshop and attempted to use the Detail Extractor function in Color Efex Pro 4. Even after reading the codicil about CMYK and grayscale, I thought, It is an RGB file; I just took out the color!

Lesson: Never, ever attempt to remove color before enhancing details.

Thanks again for replying.

If you convert using LR, then a greyscale converted image actually becomes an RGB image with R=G=B by default, and you actually cannot change that behaviour. In ACR you have the option to export a greyscale image as either an RGB with equal values, or as a true single channel greyscale image. The advantage for true greyscale, especially in an uncompressed TIFF is that it takes only a third of the space of an RGB file, where the other two channels only contain duplicate data anyway. So as long as you make sure you export as RGB not Greyscale data you should be OK using the ACR mixer for your monochrome conversion, it is my prefrerd method, even over using SilverFX.

Alan

In ACR I clicked on the description of the file at the bottom of the window to open the Workflow Options panel. Under Color Space I changed Gray Gamma to RGB, then I opened the file in Photoshop. The Nik plug-ins are now available.

Bingo! Thanks, Alan.

Next, the problem is going to be remembering to do that.

Glad to be of assistance. I just wish it were possible to export true greyscale images from LR. At the moment I have to export from LR in an RGB colourspace, then convert in PS.

Alan