Microsoft 365 Exchange Online offers various types of mailboxes that serve different purposes, from archive mailboxes to inactive mailboxes. Each mailbox type has unique features and functionalities that can help improve email management in your organization. In this blog post, we will discuss the five types of mailboxes in Microsoft 365 Exchange Online and explain how to create them using the GUI method.

1.  Archive Mailboxes   

Archive mailboxes in Exchange Online are a great way to free up space in users' primary mailboxes while still allowing them to access their old email messages. Here's how to create an archive mailbox:

1. To manage archive mailboxes in Exchange Online, you must first sign in to the Microsoft 365 Admin Center.

• Note: You'll need to have administrative credentials to access this tool.

2. Once you log in to the Microsoft 365 Admin Center, click on "Exchange" in the left-hand menu. This will take you to the Exchange admin center, where you can manage Exchange Online features and functionality.

3. In the Exchange admin center, select "Recipients" from the left-hand menu, and then click on "Mailboxes". This will show you a list of all the mailboxes in your Exchange Online environment.

4. From the list of mailboxes, select the user for whom you want to create an archive mailbox. You can also search for the user by name or email address using the search bar at the top of the page.

5. Once you've selected the user for whom you want to create an archive mailbox, click on "Enable archive" in the right-hand pane. This will start the process of creating an archive mailbox for that user.

6. You'll get a prompt to provide some additional information to complete the process of creating the archive mailbox. This may include specifying the location for the archive mailbox, setting retention policies, and more. Follow the prompts to provide the necessary information and complete the process.

7. Once you've created an archive mailbox for a user, you can manage it in various ways.

• Instance: You can set up retention policies to delete old email messages from the archive mailbox after a certain period of time automatically. You can also grant access to the archive mailbox to other users or groups, and you can search the archive mailbox for specific messages or content.

2. Shared Mailboxes:    

Shared mailboxes in Exchange Online allow multiple users to access a single mailbox, making them a great solution for departments or teams that need to collaborate on email messages. Here's how to create a shared mailbox:

1. Click on "Exchange" in the left-hand menu after logging in to Microsoft 365 Admin Center as an administrator. Once you're in the Microsoft 365 Admin Center, click on "Exchange" in the left-hand menu. This will take you to the Exchange admin center, where you can manage all aspects of Exchange Online.

2. From the Exchange admin center, select "Recipients" and then click on "Shared". This will take you to the shared mailboxes page, where you can manage existing shared mailboxes and create new ones.

3. To create a new shared mailbox, click on "New" and then follow the prompts to configure the mailbox settings. You'll need to specify a name for the mailbox, a unique email address, and other basic settings.

4. Once you've created the shared mailbox, you'll need to add the desired users to it and configure permissions as needed. You can add users from your organization or external users, depending on your needs. You can also configure permissions for the shared mailbox, such as who can send messages on behalf of the mailbox or who can access the mailbox's calendar.

5. Depending on your organization's needs, you may need to configure additional settings for the shared mailbox.

For example, you can configure automatic replies, email forwarding, and other advanced features.

6. Once you've created and configured shared mailboxes in Exchange Online, you can manage and monitor them in various ways.

For example, you can view the status of shared mailboxes, modify mailbox settings, add or remove users, and more.

3. Resource Mailboxes:    

Resource Mailboxes in Exchange Online allow you to manage resources such as meeting rooms and equipment. This feature is useful for scheduling meetings and events. Here's how to create a resource mailbox:

1. Once you're logged in to the Microsoft 365 Admin Center, click on "Exchange" in the left-hand menu. This will take you to the Exchange admin center, where you can manage all aspects of Exchange Online.

2. From the Exchange admin center, select "Recipients" and then click on "Resources". This will take you to the resources page, where you can manage existing resource mailboxes and create new ones.

3. To create a new resource mailbox, click on "New" and then follow the prompts to configure the mailbox settings. You'll need to specify a name for the mailbox, a unique email address, and other basic settings.

4. Once you've created the resource mailbox, you'll need to configure the settings for it. Resource mailboxes in Exchange Online have a number of configurable settings, including scheduling policies, availability settings, and resource capacity settings. You can also configure permissions for the resource mailbox, such as who can book the resource and who can manage the resource mailbox.

5. Depending on your organization's needs, you may need to configure additional settings for the resource mailbox.

For example, you can configure automatic booking of the resource, delegate access to the resource mailbox, and more.

6. Once you've created and configured resource mailboxes in Exchange Online, you can manage and monitor them in various ways.

For example, you can view the status of resource mailboxes, modify mailbox settings, and more.

4. Linked Mailboxes:   

Linked mailboxes in Exchange Online provide organizations with a hybrid environment to link a mailbox in their on-premises environment with a mailbox in Exchange Online. This feature allows organizations to move mailboxes between the on-premises and online environments easily. Here is a detailed step-by-step process for creating and managing linked mailboxes in Exchange Online:

Creating a linked mailbox in Exchange Online:

1. Connect to Exchange Online PowerShell by running the following command:

1. Connect-ExchangeOnline

2. Run the following command to create a new linked mailbox:

1. New-RemoteMailbox -UserPrincipalName <UPN> -OnPremisesOrganizationalUnit <OU> -LinkedDomainController <FQDN of the DC> -LinkedMasterAccount <On-premises user account> -Alias <Mailbox alias> -Name <Mailbox display name> -Password (ConvertTo-SecureString "<Password>" -AsPlainText -Force) -PrimarySmtpAddress <SMTP address>

3. Once the command has completed successfully, the linked mailbox will be created in Exchange Online and linked to the on-premises mailbox.

Managing linked mailboxes in Exchange Online:

1. Connect to Exchange Online PowerShell by running the following command:

1. Connect-ExchangeOnline

2. Run the following command to view all the linked mailboxes in your organization:

1. Get-RemoteMailbox -Filter {RecipientTypeDetails -eq 'LinkedMailbox'}

3. To modify a linked mailbox, run the following command:

1. Set-RemoteMailbox <Mailbox identity> -<Parameter> <Value>

4. To unlink a linked mailbox, run the following command:

1. Disable-RemoteMailbox <Mailbox identity>

It's important to note that before creating linked mailboxes in Exchange Online, the following prerequisites should be met:

• A hybrid deployment must be set up between on-premises Exchange and Exchange Online.

• The on-premises Active Directory must be synchronized with Azure Active Directory using Azure AD Connect.

• The Exchange Online organization must be configured with the correct federation settings.

By following the above steps and ensuring the prerequisites are met, organizations can successfully create and manage linked mailboxes in Exchange Online as part of their hybrid environment.

5. Inactive Mailboxes:   

Inactive mailboxes in Exchange Online allow you to retain the mailbox content of a departed employee without the need to assign a license to that mailbox. They can be accessed by administrators and can be converted back to active mailboxes if needed.

To create an inactive mailbox in Exchange Online, follow these steps:

1. Sign in to the Microsoft 365 Admin Center.

2. Click on "Exchange" in the left-hand menu.

3. Select "Recipients" and then click on "Mailboxes".

4. Click on "New" to create a new mailbox.

5. Select "User Mailbox" and then follow the prompts to create the mailbox for the departed employee.

6. After the mailbox is created, go to the "Mailbox Features" tab and disable all features except for "Archive".

7. Save the changes and wait for the mailbox to be created.

For converting an active mailbox inactive, follow these steps:

1. Click on "Exchange" in the left-hand menu.

2. Select "Recipients" and then click on "Mailboxes".

3. Select the mailbox that you want to convert to an inactive mailbox.

4. Go to the "Mailbox Features" tab and disable all features except for "Archive".

5. Save the changes and wait for the mailbox to be converted.

To convert an inactive mailbox back to active, follow these steps:

1. Click on "Exchange" in the left-hand menu.

2. Select "Recipients" and then click on "Mailboxes".

3. Select the inactive mailbox that you want to convert to an active mailbox.

4. Go to the "Mailbox Features" tab and enable the desired features.

5. Save the changes and wait for the mailbox to be converted.

Note that inactive mailboxes can be accessed by administrators using PowerShell or the Exchange Admin Center. The mailbox content can be exported, searched, or deleted as needed. Inactive mailboxes are retained for an indefinite period of time, and they do not count towards the organization's mailbox quota.

If you are keen in understanding how to remove an exchange server mailbox from your environment, follow the embedded link.

Conclusion