How To Disable OWA To All Users Exchange 2010 / 2013

If you need to disable OWA access to all user In your organization In one go or In bulk you can use Exchange Poweshell.

To disable OWA open EMS and type:

Get-Mailbox -ResultSize unlimited |Set-CASMailbox -OWAEnabled $false

To enable it back to all users type:

Get-Mailbox -ResultSize unlimited |Set-CASMailbox -OWAEnabled $true