A friend of mine is getting a pop up window asking her to sign into her iCloud account and it is from iCloudd. Note there are 2 D's. Is this malware or a virus? If so what can she do?
cloudd is the name of one of the background processes involved with iCloud. Certainly, Sierra is more secure than Yosemite, and more stable. I would suggest your friend sign out of iCloud and then sign back in and see if the problem persists.