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Your Definitive Guide to Mount/Dismount Exchange Database with Ease!

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Published By Ashwani Tiwari
Ashwani Tiwari
Approved By Ashwani Tiwari
Published On November 28th, 2024
Reading Time 8 Minutes Reading
Category Exchange Server
Managing an Exchange Server involves numerous tasks, and one of the most critical responsibilities for Exchange administrators is ensuring that databases are properly mounted and dismounted. Mounting and dismounting Exchange databases are essential operations for maintaining a smooth-running mail system, performing maintenance, and recovering from failures. In this guide, you will learn about the mount/dismount Exchange Database, including manual methods, and troubleshooting tips. 

What is Mounting and Dismounting an Exchange Database?

Now, let’s have a look at the concise overview of the mount & dismount of the Exchange database –

#Mounting an Exchange Database

Mounting an Exchange database means making a database accessible in an Exchange Server. When you mount a database, you enable users to access their emails, calendars, and other data stored within the database. Without mounting, the database is not active and cannot be accessed by users.

#Dismounting an Exchange Database

Dismounting a database makes it inaccessible to users. This is typically done during maintenance, backup operations, or when troubleshooting issues. Dismounting is a safe way to stop access to the database for users.

Understanding the Reasons to Mount & Dismount Exchange Database!

In many situations, mounting or dismounting a database is required, and the below table shows the cases for both of them in detail –

Mount/Dismount Exchange Database

Direct & Quick Techniques for Mounting and Dismounting Exchange Databases!

Exchange Server provides several ways to mount and dismount databases, but here we discuss the best and tested methods i.e. Exchange Admin Center (EAC), EMS, Command Line, and EMC

Before starting with the procedure, ensure that the database is healthy by running this command eseutil /mh “<DatabaseName>.edb” because corrupt data can’t be mounted or dismounted. Additionally, if the database is severely corrupt and standard repair methods fail, tools like the MS Exchange Recovery Tool become invaluable. This solution can repair highly corrupted databases simultaneously and recover data even from dismounted or inaccessible databases. 

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Method 1: Use the Exchange Admin Center (EAC) to Dismount & Mount Exchange database

The Exchange Admin Center (EAC) is a web-based management console, that helps to repair EDB Exchange database and manage Microsoft Exchange Server easily. Additionally, we can use this also for mounting and dismounting the databases by following these steps –

Steps to Mount:

  1. Open the Exchange Admin Center by opening https://<ExchangeServer>/ECP in a web browser.
  2. Click Servers, then select Databases.
  3. From the list of databases, choose DB for mount.
  4. If the database is dismounted, you will see an option to Mount it. Click Mount.

Steps to Dismount:

  1. Open the Exchange Admin Center.
  2. Navigate to Servers > Databases.
  3. Select the database to dismount.
  4. If the database is mounted, you will see an option to Dismount it. Click Dismount.

Method 2: Using Exchange Management Shell (EMS)

PowerShell commands make automated & feasible to mount/dismount Exchange database, but this approach is quite complex and technical to understand. So, it is suggested to run the commands carefully –

Steps to mount:

  • Open the Exchange Management Shell and verify the correct database for mounting by running this command.
Get-MailboxDatabase
  • Now, for mounting run this –
Mount-Database –Identity <databasename e.g., > –Confirm:$False
Note – If you find your data is corrupted then repair corrupt Exchange database, use this command for recovery eseutil /r E00 /l “C:\Path to log file” /d “C:\Path to database”. Then use eseutil/mh to verify whether the database is healthy or not. 

Steps to Dismount Exchange Database:

  • To dismount a specific database, use the following command:
DisMount-Database –Identity <databasename> –Confirm:$False
  • Dismounting several databases simultaneously runs this –
Dismount-Database –server <database name> –Confirm:$False
  • Add the -Force parameter, if you want to forcefully dismount it, follow the cmdlets:
Dismount-Database -Identity "Mailbox Database 1" -Force

Method 3: Dismount/Mount Exchange Database Using the Command Line (Legacy Method) 

PowerShell is the advanced option that is used for newer versions of Exchange. However, older versions, still need a command line for mounting and dismounting –

Steps to Mount an Exchange Database using Command Line:

  • Run Command Prompt with administrator access.
  • Go to the Exchange Server’s bin directory, located at C:\Program Files\Microsoft\Exchange Server\V15\bin\.

To mount the DB, run the cmdlets:

eseutil /m <database filename>

Steps to Dismount an Exchange Database using Command Line:

  • Start Command Prompt as an administrator.
  • Run the following command to dismount the database:

eseutil /d <database filename>

Method 4. Mount a Database in Exchange 2010 Using EMC

These instructions are especially for those who using Exchange 2010 –

  • Start > All Programs > Microsoft Exchange 2010 > Exchange Management Console.
  • Go to the mailbox databases > Expand Server Configuration > Click Mailbox.
  • Find the dismounted database in the middle pane.
  • Right-click the database and select Mount, or click Mount in the action pane.
  • Click Yes to confirm the mount.

Steps to Dismount an Exchange Database – 

  • Follow the steps 1 & 2 mentioned above.
  • Find the mounted database in the middle pane.
  • Right-click the database and select Dismount.
  • Click Yes to confirm the dismount.

Troubleshooting Common Issues!

Mounting and dismounting Exchange databases is a straightforward process, but occasionally, users encounter some issues like Exchange not receiving external emails during the procedure. Listed are the same with solutions:

Issue 1: Database Won’t Mount

This issue often occurs due to database corruption, missing transaction logs, or permission issues. Here are a few troubleshooting steps:

  • Check the Event Viewer for relevant error messages.
  • If transaction logs are missing or corrupted, restore them immediately or start recovery.
  • Use the eseutil tool to repair the database. Run the command:
eseutil /p <database filename>

Issue 2: Database Mounts but Users Cannot Access Mailboxes

In some cases, database mounts successfully, but still users cannot access their mailboxes. This can be due to insufficient permissions, corrupt mailbox databases, or active directory problems.

  • Ensure you provide all the necessary permissions to access the data.
  • The specified repair tool can fix minor or major corruptions quickly.

Issue 3: Database Mounting Takes Too Long

If the mounting process takes longer than expected, this could be due to database size, or disk performance issues. Consider running the following checks:

  • Ensure the disk subsystem is performing optimally.
  • Reduce Exchange mailbox size to minimize the time.
  • The dbcc check can be used to verify database integrity.
Essential Best Practices for Mounting & Dismounting Exchange Databases!

To avoid disruptions or complexities, read and implement this checklist to initiate the task efficiently –

  • Always back up databases before dismounting for data recovery purposes.
  • Perform mounting operations during off-peak times to reduce user disruptions.
  • Ensure database replicas are synchronized before mounting or dismounting databases.
  • Check for corruption using eseutil and IsInteg before mounting databases to avoid data loss.
  • Review event logs frequently to detect potential issues during operations.
  • Test database recovery processes to ensure fast restoration when necessary.
  • To check if your user account has the required roles, run:
Get-ManagementRoleAssignment -RoleAssignee "username e.g. Joe"
  • If the Databases role is missing, assign it using –
New-ManagementRoleAssignment -Name "<AssignmentName>" -User "<Username>" -Role "<RoleName>"
  • After assigning the role, verify it by running –
Get-ManagementRoleAssignment -RoleAssignee "admin"
Overall Summary!

Mounting and dismounting Exchange databases becomes crucial when managing Exchange Server. Understanding when and how to mount or dismount a database is critical for Exchange administrators. By using the manual methods outlined above, Admins can efficiently manage Exchange databases and troubleshoot common issues. Remember, for severe database corruption tools like the aforementioned will help to make the content healthy for further processing.

Got Questions? We Have the Answers!

Q1. What happens if I accidentally dismount an Exchange database?

Dismounting an Exchange database will stop users from accessing their mailboxes. It will be available after mounting. However, your data is safe whether you dismount data accidentally or intentionally.  

Q2. Is it possible to mount a database without transaction logs?

No, it is not recommended! As it can lead to data inconsistencies. However, in certain recovery scenarios, you can mount the database without logs using the eseutil /r command.

Q3. How to recover a corrupted Exchange database that won’t mount?

Uncorrupting the DB is necessary before mounting, and using these commands will help in this-

#For Dirty Shutdown State

eseutil /p "C:\Path\To\Database\MailboxDatabase.edb" 

#For Minor issues with mailboxes

New-MailboxRepairRequest -Mailbox <MailboxIdentity> -CorruptionType All