You need to set up an @email address before you can use i Cloud Mail.
If you didn't set up an i Cloud Mail account at the same time as your i Cloud account, the Mail option in your i Cloud for Windows account might be grayed out.
And you don't need to have the third eye to understand at least one reason why they discontinued it.
If you have multiple i Cloud accounts, you might be logged in to i Cloud for Windows with a different account than you are on your other devices.To check, open i Cloud for Windows and compare it with your other devices.Information about products not manufactured by Apple, or independent websites not controlled or tested by Apple, is provided without recommendation or endorsement.Apple assumes no responsibility with regard to the selection, performance, or use of third-party websites or products. Other company and product names may be trademarks of their respective owners.
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I'm sure by now all of you are aware that the old good Google Calendar Sync is not supported any longer.