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Check Exchange health mailboxes

DAG databases keep switching servers by themselves is a new feature of Exchange 2016 CU2. If you have a pre Exchange 2016 CU2 server and it is switching over automatically, then there is another issue. What you need to do is to check the Exchange health mailboxes. Did you already check the Exchange health mailboxes? If the health mailboxes are corrupted, then it will not work like it is intended to do.

How many Exchange health mailboxes

Up to Exchange 2013 CU6, there is one health mailbox per mailbox database copy and one per 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.

If you need to know the total count of the health mailboxes, run the following command.

The organization is running 2 Exchange 2016 Servers with a DAG configured. Each Exchange Server is running 12 databases. Let’s do the math:

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

Now that we have calculated the count of the health mailboxes, we can proceed further to check the health mailboxes.

Check Exchange health mailboxes

Open up Exchange Management Shell as Administrator. Check the health mailboxes of all the Exchange servers in the organization. We did not list all the health mailboxes, it should show like below.

If you have more then one Exchange Server and you want to show the health mailboxes of that particular Exchange Server, run the following command.

It will list all the health mailboxes and if you don’t see any error, all is good! If you see errors on one or more health mailboxes, it means that the health mailboxes are corrupted and in an inconsistent state.

“WARNING: The object DOMAINNAME/Microsoft Exchange System Objects/Monitoring Mailboxes/”Health_Mailbox_GUID” has been corrupted, and it’s in an inconsistent state. The following validation errors happened: WARNING: Database is mandatory or UserMailbox.”

Fix corrupted inconsistent state Exchange health mailboxes

Stop the service Exchange Health Manager Service on all the Exchange Servers.

Open up Active Directory Users and Computers(ADUC) and open up the group Microsoft Exchange System Objects. You will see a subgroup called Monitoring Mailboxes. Select that group.

Select all the health mailboxes and delete them.

If you want to delete them through Exchange Management Shell, run the following command.

Now let’s recreate the health mailboxes.

Start the service Exchange Health Manager Service on all the Exchange Servers. You can also restart the Exchange Servers.

It may take a while for all health mailboxes to be populated. Run the following command again to check if all is looking good.


It’s always important to have the health mailboxes checked. Having all health mailboxes in proper state is important to keep your Exchange Servers healthy. When was the last time that you checked your health mailboxes? Another great article about the health mailboxes is written by Microsoft. If you enjoyed this article, you may also like Exchange transaction logs growing rapidly. Don’t forget to follow us for more great content.



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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