Updated: 12-07-2018
https://www.apple.com/icloud/setup/mac.html
Sign in to iCloud to access your photos, videos, documents, notes, contacts, and more. Use your Apple ID or create a new account to start using Apple services.
Then set up iCloud for your iPhone, iPad, iPod touch, or PC. To update to the latest version, go to the Apple menu and choose Software Update to see if there's an update available. Choose System Preferences
https://www.apple.com/icloud/setup/mac.html
iCloud Support. All the topics, resources, and contact options you need for iCloud. Sign in to iCloud on your device. Sign in to iCloud on the web.
https://support.apple.com/icloud
Mar 24, 2015 - Enable iCloud Password Login and Unlock Mac with OS X. Go to the ? Apple menu and choose “System Preferences” from the dropdown menu. Choose the “Users & Groups” panel and select the
http://osxdaily.com/2015/03/24/use-icloud-password-as-m...
Mar 4, 2015 - Fix for Mac Randomly Asking for Password to iCloud, FaceTime, Messages. ... I also randomly got the same popup to sign in to iCloud on my ...
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