1. Log into Azure PowerShell and sign into your tenant
2. Connect to Office 365 with the Connect-MsolConnect cmdlet.
3. Run: Set-MsolDirSyncEnabled EnableDirSync $false
How can we check that this has worked?
Microsoft states that “If you disabled directory synchronization, deactivation may require up to 72 hours.”
Microsoft KB: https://support.microsoft.com/en-us/kb/2619062