Mailboxes in Exchange Server – Overview of Different Mailbox

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Overview of Mailbox in Exchange Server 2013/10/07. Mailbox such as User Mailbox, Legacy, Shared, Resource, Room, Equipment, Linked, Disconnected is created in Exchange Server. Also, Arbitration, Discovery Mailbox, Mail Contact & Mail User used to data in Exchange with Public Folder and Site Mailbox.

Exchange Server is collaborative Enterprise Server application that supports Email, Calendaring, Data, Storage and other advanced services. But still, Exchange Administrators and users are often unaware about the number of mailboxes in Exchange Server. 

There are Four different types of mailboxes associated with Microsoft Exchange Server. Therefore, in this blog, we are going to discuss various mailboxes present in Exchange Server. On the basis of Exchange Objects, the mailboxes are divided into four segments to understand easily such as “Mailbox”, “Storage” “Contacts” and “System Mailbox”. Each Section holds a different kind of mailbox to help the Administrator in different scenarios and conditions. Powershell commands can be used to view Exchange mailbox details such as file size, item count, and other details easily.

Different Types of Mailboxes in Microsoft Exchange Server

Basically, Exchange Server mailbox is an Exchange object which is used to send or receive emails. Additionally, it also stores messages, tasks, documents, appointments etc. Various types of mailboxes in Exchange Server are explained in the section given below:

  • User Mailbox: The basic object of any Exchange System is User Mailbox. These mailboxes provide users a rich collaboration platform. In an Exchange organization, user mailboxes are assigned to individual users. The user mailbox is directly linked to any user account in Active Directory. The user can perform various tasks under this mailbox such as send and receive messages, contact management, schedule meetings etc.

  • Legacy Mailbox: This mailbox is available in Exchange organization which is created from the earlier version of exchanger servers. One can say that when there is a co-existence of the previous and new version of Exchange system. Then all the mailbox objects in the older version are called as Legacy.

  • Shared Mailbox In Exchange: It is an object that is generally configured to allow access by multiple users. These type of mailboxes are not associated with individual users. Shared Mailbox is also known as the Common mailbox. For Ex: etc. The account of the Active Directory user must be a disabled account which is associated with the shared mailbox. If a user is creating a shared mailbox, then he/she must assign permissions to all the required users so that they all can access the shared mailbox.

  • Resource Mailbox: These are mailboxes that are similar to the shared mailbox. They are specially designed to be used for scheduling resources. They do not have a dedicated user. Similar to all the mailbox types, this mailbox also has an Active Directory user account associated to it. This must be a disabled account. There are two types of Resource Mailbox: Conference Room Mailbox and Equipment Mailbox.

  • Room Mailbox: These mailboxes are specially created for automatically booking or scheduling conference room according to the requirements. Other users can see the availability of the Rooms through the calendar. Room mailboxes In Exchange are mostly assigned to the meeting location such as auditoriums, training rooms, conference rooms etc.

  • Equipment Mailbox: These type of mailboxes are designated for the resources that are not location-oriented such as microphones, portable computers, projectors or company cars.

  • Linked Mailbox: These mailboxes are accessed by the users in a separate, trusted forest. When the Active Directory user account and Exchange Mailbox lies in a different forest then they are known as Linked Mailbox.

  • Disconnected Mailbox: It is a deleted mailbox. If a mailbox is detached from the Active Directory account or when the AD account is deleted then the mailbox becomes inaccessible. Then it is called as a Disconnected Mailbox. By default, till 30 days it will be in the disconnected state. After that, it will be removed. During this time, the user can re-attach the disconnected mailbox to the user’s account or any other Active Directory account.

Storage Mailbox

In Storage Section of Exchange Objects, Two Folders are included and used to hold data that can be used in various Exchange clients easily.

  • Public Folder: Basically, public folders are used to store emails and data. They are part of Exchange systems. These folders are public to everyone that means they can be accessed by any user. But they can also be restricted with permissions.

  • Site Mailbox: This mailbox is mainly used for SharePoint purposes. The users can send documents as an email to this mailbox. This mailbox can be stored and shared in SharePoint sites. The user can also configure the Site Mailbox of a SharePoint site in Outlook to access the data.

Contacts Section In MS Exchange Server

  • Mail Contact: The main purpose of using Mail Contacts is displaying external email address in the Global Address List (GAL) and also adding them in Distribution Groups. Used to stores information about People and Organization of Inside & Outside Exchange

  • Mail User: It is an Active Directory object. It does not have an in-house mailbox. Basically, it is a user account. The main reason behind creating these objects is providing access to the in-house resources such as computers, printers etc. It holds login information for Exchange. Basic information such as “First Name, Last Name, Organizational Unit, Login Name and Password” stored in it.

System Mailbox In Exchange Server

  • Arbitration Mailbox: It is used for approval mechanism and workflow. These mailboxes are used for Distribution Groups, Transport Rules etc. The mail sent to these objects are first sent for approval to the respective owners. These sent emails will be temporarily stored in the arbitration mailboxes until the owner approves or reject those emails.

  • Discovery Mailbox: These mailboxes are the hidden mailbox. It is used for Compliance and legal purpose and used for e-discovery purposes [process to find, locate, store and used as evidence in criminal legal case]. By default, Discovery Mailbox is Created with 50 GB storage quota limit and to access is, permissions are needed. This Mailbox cannot be managed via Exchange Admin Center but Powershell used this purpose.

Repair Exchange Mailboxes

Lots of mailbox objects created in Exchange and some time Exchange Administrator not able to access user mailboxes due to Corruption Issues in Exchange Database File [EDB] and manual methods such as “Eseutil, Inisteg” Commands not helpful to repair an exchange database. An automated solution needed in this situation recover back deleted emails and other items.

Try SysTools Exchange Recovery Tool to Fix Corruption Issues and Restored back EDB mailboxes in the Different file format such as PST, MBOX, EML. HTML and MSG file format. Also, option to save back data into Live Exchange Server and Office 365 Account is also possible with the Exchange Recovery Software. Try Demo version of Software from below Link: 

To learn more about this Software, visit:

Final Words

In the above section, we have discussed different types of mailboxes in Exchange Server. Each mailbox plays an important role and has a unique purpose in MS Exchange Server. Some Mailboxes used actively, whereas other mailboxes used in Specific Condition and scenarios. 

Some Exchange users are still unaware about the mailboxes explained above. Therefore, with the help of this blog, users will be able to understand about each mailbox in an easy way and if any Exchange Administrator faces problem-related to corruption can be Fixed via SysTools Exchange Recovery Tool without data loss.

SysToolsData Expert - Recovery,Backup,Migration
SysTools Simplifying Technology Leading  in Data Recovery, Data Migration & Data Backup With 200+ Solutions.

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