Saved iCloud passwords requested on startup
Saved iCloud passwords requested on login for my iMac (Retina 5K, 27-inch, Late 2014). OS X Yosemite 10.10.5
This happened on startup after being shutdown for the night. The first time it happened other passwords were requested including a Facetime password. Dismissed each by clicking cancel but more appeared. After a restart, only an iCloud password is requested and doesn't come back after being dismissed twice.
I had a similar issue with Mail that I was able to fix by unchecking “Automatically detect and maintain account settings. " and manually adjusting mail settings.
I ran Keychain First Aid but that had no effect. This is also happening on my MacBook Pro (Retina 15-inch, Early 2013) OS X Yosemite 10.10.5 but only for my wife's account when she logs in.
iMac (Retina 5K, 27-inch, Late 2014), OS X Yosemite (10.10.3)