Open Powershell as administrator (by right-clicking on the windows button).
Copy and paste this in the window: Get-appxprovisionedpackage –online | where-object {$_.packagename –like “*windowscommunicationsapps*”} | remove-appxprovisionedpackage –online
Click Enter to run
Re-install Mail, People and Calendar from the old Store (the one with the green tile).
