I'm continuing to get this error:
But as you can see the Source and the Working are the same RGB. I ignore the error, and most of the time it pastes just fine. However, sometimes it crashes my Photoshop and the error seems to be occurring more frequently. I'm running Yosemite and have Photoshop CS6.
It stated the destination document is Generic RGB Profile. I use a PC My pop-up only shows two Source and Destination. It looks like Mac may also show your color setting default Working color space. Perhaps one of the document opened has a Generic RGB profile and you color setting are set to preserve the documents profile and not to prompt if different then your working profile.