How to Fix Exchange Database Failed to Mount Error?

Published: Jul 01, 2024

Datacenter networking servers

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When mounting a database on Exchange Server, you may face a situation where the database does not mount and an error message appears, saying, “Failed to mount the database.” An Exchange database may fail to mount for various reasons. In this article, we will be discussing the reasons that may lead to the ‘Exchange database failed to mount’ error and ways to fix it.

This article is sponsored by Stellar Info.

Reasons for Exchange database mounting error

There are several reasons that can cause the Exchange Server database mounting error. Here are some of the most common:

  • Lack of disk space where the database is stored.
  • The database might be corrupt or damaged. This can happen due to sudden loss of power, hardware failure, sudden shutdown of the server, etc.
  • Antivirus software, backup software, or any other third-party software, which is not compatible with the version of Exchange Server installed. Third-party software might lock or delete important Exchange Server files, damaging the integrity of the database.
  • Issue with licensing. For example, you have the Standard license of Exchange Server, which allows mounting of five databases but you’re trying to mount an additional database.

Methods to resolve the Exchange database mounting error

Here are some solutions you can try to troubleshoot and resolve the Exchange database mounting error.

Note: Before attempting to troubleshoot the error, make a backup of the Exchange database. Also, run the Exchange HealthChecker script to see the overall configuration and health status of your Exchange Server.

1: Check Exchange Server services

The first thing you need to do is check the services running for Exchange Server. You can go to the Services Control Panel to check and ensure that the right services are started.

Restart services to fix the Exchange database failed to mount error
Restart services to fix the Exchange database failed to mount error (Image Credit: Petri.com/Bharat Bhushan)

If the services are running, you can try to restart them.

2: Check disk space

If the server is not backed up or the backup software is not compatible with Exchange Server, then the database transaction logs will not commit changes. This means that the transaction logs will keep on increasing, eventually filling up the disk. You should always ensure that there is enough space on the disk for the transaction logs and database are located.

To purge the transaction logs, make a full backup of the server (if possible). If not, then you can use Windows Server Backup to simulate the application backup. You can use the commands below to purge the transaction logs.

Diskshadow
add volume m:  <This being the drive letter of the data drive>
begin backup
create

This will begin the process. When finished, type the following command:

End backup

This will release the storage by committing and purging the transaction logs.

3: Restore from backup

You can also consider restoring the Exchange Server database from the last healthy backup. However, you may lose the data from when the server backup was taken to when the issue occurred. After restoring the database, check its status. If it is in Dirty Shutdown state, run the EseUtil command to perform a soft recovery.

4: Repair the Exchange database

The database will not mount if there are missing/corrupt transaction logs or the database is corrupt. In this case, you can use the Exchange Server EseUtil tool to perform a soft recovery or hard recovery.

First, you need to check the state of the database by running the command below:

eseutil /mh <database file path>

If the status is Healthy Shutdown, you can try to mount the database. However, if there are missing transaction logs or the database is corrupt, it will show the status as Dirty Shutdown. In this case, you need to perform a soft recovery:

EseUtil /r <edb database file path>

This will perform a quick recovery of the database and try to fix minor issues with the database and/or transaction logs.

If this fails, then you can perform a hard recovery:

eseutil /p [database file path]

Note: This process will simply purge anything which is deemed corrupted. Although this might allow you to mount the database, there will be a significant amount of data loss. This operation will take a considerable amount of time and disk space. In addition, there is no guarantee that it will fix the problem.

To avoid data loss, you can use a specialized Exchange database recovery tool, like Stellar Repair for Exchange. The tool can easily repair corrupt databases and recover all the data, including user mailboxes, archives, shared mailboxes, disabled/deleted mailboxes, purged/deleted items, and public folders. You can then granularly export the recovered data to PST and other file formats. You can also export the EDB data directly to live Exchange Server databases or Office 365.

Implement preventive measures to avoid the Exchange database failed to mount error

There are multiple things that could go wrong during everyday operations that can lead to the Exchange database mounting error. In this article, we have discussed the troubleshooting steps to resolve the problem. If the database is corrupt, you can use EseUtil to perform a soft or hard recovery. However, EseUtil has some limitations.

As an alternative, you can use Stellar Repair for Exchange to fix the corrupt Exchange database without any data loss. You should implement preventive measures, like monitoring systems to track CPU, memory, storage, and events on the server to avoid issues with Exchange, Windows, and database mounting errors in the future.

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