An ongoing problem in Illustrator in some files and I'm not sure what the cause of the issue is:
When I attempt to select color using the eye-dropper tool in some Illustrator documents, the color picker only picks up white. I have to take a screenshot and then paste that back into the document as a bitmap for the color picker to work properly. I have tried using the SHIFT-key and I did check the double click options, all looks good. The document color space is CMYK.
My personal opinon on the eye dropper: I only use it for transfering font styles or colors - I never use any of the other features. Font style transfer seems to work OK, but color transfer has been a problem as long as I can remember (except right after it was introduced, it did work flawlessly for a while).
BTW: I can't post the Illustrator version, as this is so hidden that I just gave up searching for it. I have the newest update. It used to be straighforward to get the version number, just click on Help and find the version number. When I click system info in "Help" now, I get the AUTOCAD versions??? Some things in cc have become pretty ridiculous...
For anyone who would like a dedicated color picker that works flawlessly and can also pick colors from anywhere (other apps, desktop screens and any open web-browser window), please upvote my feature request at Adobe here.
Version is in "About Illustrator" one up from "System Info"...
Most of the time my eyedropper works fine but every once in a while it won't grab a color from an embedded file, usually something with an imperceptable gradient fill and I'm forced to unembed which is not always the best solution.