Discovering which users have logged into Outlook Web App (OWA) compared to those who haven’t is a bit of a challenge in Exchange Online and Exchange Server 2013/2016. One method is to make use of the fact that prior to first login, a user won’t have selected their language. Using this piece of knowledge allows us to perform a (somewhat rudimentary) evaluation of which users probably have logged into OWA.
Connect to Exchange PowerShell and run the following:
Easy! This will show you each mailbox and by evaluating the “Language” value for each, you can determine if a user’s logged into OWA or not. Let’s make it even easier:
The really easy way
Cmdlets used in this post
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