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Count health mailboxes in Exchange

In this article, you will learn how to count health mailboxes in Exchange Server. You will learn how many health mailboxes are present in each Exchange Server organization. Get a better understanding of the health mailboxes. Why we need the health mailboxes and since when we have health mailboxes in Exchange Server. Let’s dive into it.

Health mailboxes in Exchange Server

Exchange Server 2013 introduced a new feature called Managed Availability. Managed Availability is a built-in monitoring system with self-recovery capabilities. Managed Availability performs continuous tests (probes) that simulate end-user actions. It does that to detect possible problems with Exchange components or their dependencies. If probes are failing, it performs gradual simple recovery actions. This way it will bring the affected component in a healthy state. It uses a special type of mailboxes, called monitoring mailboxes or health mailboxes. These mailboxes simulate end-user kinds of tests. The life cycle of monitoring mailboxes is taken care of entirely by Managed Availability components.

In the next part, you can count the health mailboxes in ADUC.

Count health mailboxes in Active Directory Users and Computers

Go to Active Directory Users and Computers (ADUC) to check the health mailboxes. Make sure to enable Advanced Features in ADUC. If you don’t, you are not able to see the Organizational Unit (OU) Microsoft Exchange System Objects.

Count health mailboxes Exchange in ADUC

How many health mailboxes in Exchange

Up to Exchange 2013 CU6, there is one health mailbox per mailbox database copy and one per Client Access Server (CAS). Exchange 2013 CU6 changed the amount of health mailboxes that are created. A health mailbox is created for every mailbox database hosted on a mailbox server (Active or Passive) and 10 health mailboxes for every CAS role.

Get total count health mailboxes with PowerShell

Count the health mailboxes in Exchange Server with PowerShell.

The math behind the count

Let’s have an example of an organization that is running two Exchange 2016 Servers with a DAG configured. Each Exchange Server is running twelve databases. Let’s do the math:

2 Exchange Servers * 12 databases = 24 health mailboxes
2 Exchange Servers (CAS role) * 10 health mailboxes = 20 health mailboxes
Total = 44 health mailboxes

Read more about health mailboxes in Exchange Server: Check Exchange health mailboxes »


In this article, you learned how to count health mailboxes in an Exchange organization. Calculate the health mailboxes and make sure that they are present in ADUC. How many health mailboxes are present in your Exchange environment? The Exchange team at Microsoft did write a great article about health mailboxes.

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ALI TAJRAN is a passionate IT Architect and IT Consultant. His specialism is designing and building complex enterprise environments. He started Information Technology at a very young age, and his goal is to teach and inspire others. Connect with ALI TAJRAN on social media. Read more »

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