Powerpoint Office2016 Eyedropper not working

I, too, had this problem. Ran Office 365 ProPlus "Office Updates", which took PowerPoint from Build 7369.2130 up to 7766.2092, and the eyedropper issue is now non-reproducible on my machine. Seems if you can do the updates, you should be good to go.

For those who might not be able to update Office, or do and still see the issue, here's a workaround that's not too painful: The issue only seems to affect colors in the PowerPoint application; I was able to pick colors with the eyedropper from other apps just fine. (To do this, after activating the eyedropper tool, click anywhere in a PowerPoint slide, then hold and drag the mouse to anywhere else on your desktop; release the mouse button when over the desired color.) So, to pick a color that's on the slide, screenshot the slide, then use the eyedropper to pick the desired color from the screenshot.

Hope that makes sense...