I have an external G drive used for managing my photos. When the IMAC goes to sleep and I wake it up I receive multiple pop ups G drive not ejected properly. A spinning wheel appears and I can not do anything. I am running Yosemite 1
Technically speaking...any external drive attached to a Mac is supposed to be ejected (dragged to the trash) before sleeping the computer. This is why you are getting that message. The solution is...before sleeping the computer...drag this external drive to the trash to eject it first. Or don't keep this drive always attached to the computer.