Login to Exchange Admin Center and head to servers menu. Ok, let’s define mailbox size for all our users. So, think about this before you act, and don’t just put unlimited mailbox size, you will regret that decision, especially when problems start. Mailbox size is double-edged sword – it is convenient to have large mailbox, but it can also be performance and reliability issue since large mailboxes don’t behave very well in these terms. You will hear some people protesting about limits and want larger mailboxes for email. This is setting you need to think about and take into account how many users you have,do you have a lot of large attachments, what is the physical space you have on your drives, what Exchange license you have (Standard license can have max 5 DBs) and so on… Some of these settings can be defaulted after CU update, or regular update – be sure to check limits – ActiveSync in particular, after every huge update to your Exchange! Establish what your organization needs and act accordingly. You can set attachment size limit to 300MB, but then again, nobody would be able to receive email with attachment that large. I’m going to enter some values, but in the end, you can set something entirely different. There are also limits on how many recipients can be in one message (I won’t cover that here) so be sure you also alter that if you need to send emails to large group of people.Īll of the limits we are going to set are up to you and your specific environment.

When you deploy fresh Exchange 2019 you want to set mailbox size limit for your users, retention policy for the mailboxes (how far ca nyou retrieve deleted messages) message size settings and attachment size settings (message size and attachment size are two different things), also limits for mobile devices are separate story.

I will try to go through every setting in this guide although I cannot promise I won’t miss something. Etting message and mailbox limits in Exchange 2019 isn’t easy job, there are a lot of places where the settings need to be placed.

Exchange 2016 attachment size limit