I have just upgraded from CS to CS2. Every time I open a photo edited in CS I get either an error message regarding missing embedded RGB profile or embedded grayscale profile. I have found information on these error messages but no real helpful suggestion as to which option to choose. Hope you can help me on this. Regards.
The Error message you're referring to is Photoshop's attempt to identify or place an embedded color profile in the file being opened. In a properly color-managed workflow every image that passes through should have the same color profile embedded in it. That put's all the images "on the same page", so to speak. It's just one page, however, in the volume known as color mangement. If the color on your system is OK for you, you can just turn off the warning.
Choose Edit > Color Settings
The Color Settings dialog box appears.
In the Color Management Policies section de-select the three "Ask when..." options.
That should do it.
If on the other hand you're having color issues, embedding a color profile isn't such a bad idea...I like the Adobe RGB (1998) profile, but that's another story. Learn more about the Color Setting options by rolling your cursor over each section, dropdown menu, etc. whereupon a description will appear at the bottom of the dialog box. Adobe has even provided some pre-set Settings. Surprise.