Perform Dial Tone Recovery in Exchange Server

Updated On - August 22, 2023 by Deepika Singh | Reading Time: 5 minutes

In this blog, we read about Dial Tone Recovery, its benefits, and know how to perform Dial Tone Recovery in Exchange Server.

An EDB file is an Exchange database file stored in Microsoft Exchange Server. Each Exchange Server creates one .EDB file containing all the mailboxes (emails, calendar, contacts, attachments, tasks, etc.).

Exchange database .EDB file may get corrupted due to numerous unknown reasons such as:

  • Power Outage or Unexpected Shutdown
  • Hardware Issues – Sub-standard hardware, bad sectors in a hard drive, motherboard failure, drives failure.
  • Software Problem
  • Server Crash or Failure due to OS stop error, communication issues, processor chip/motherboard/backplane failure, network issues, system overload, misconfiguration, etc.
  • Boot Failure due to malware attacks, failure/non-response of system services and other applications, hardware malfunctioning, OS failures, etc.
  • Dirty or Accidental Shutdown due to sudden power failures or user errors.
  • Incompatible Antivirus Software
  • Low Storage Space
  • Missing or Deleted Log Files
  • Exchange Database size exceeds the storage limit
  • User Errors such as stopping Microsoft Exchange Information Store Services, dismounting the wrong databases, deleting mailboxes or transaction log files, etc.

Know About Dial Tone Recovery

Dial Tone Recovery is a method in which an empty database is created on a mailbox server and replaced with a failed database. This empty database is known as Dial Tone Database, using which you can send or receive messages until the original database is repaired.

The process of allotting users a temporary mailbox for sending and receiving emails until the original mailbox becomes fully functional after repair or restoration is known as Dial Tone Portability. This feature helps businesses to maintain email continuity in case of Exchange Server failure or Exchange database issues.

Benefits of Dial Tone Recovery

  • Even if the Administrator account is corrupt, Dial Tone Recovery allows you to send or receive emails without downtime.
  • Continue to send or receive emails while the original database is being recovered.
  • Bring the database back online without impacting business operations.

Pr-requisites for executing Dial Tone Recovery

  • User must have Organization management permissions on mailboxes.
  • Must have less number of databases on the Server than the maximum allowed.

Note: Exchange 2013/2016 Standard Edition supports up to five databases per Server.

For the Enterprise Edition, there is a maximum limit of 100 databases.

Perform Dial Tone Recovery on a Single Server using Exchange Management Shell

To perform the Dial Tone Recovery on a single Server, perform the steps as discussed below:

  1. Start Exchange Management Shell.
  2. Execute the below commands:

a. To create a Dial Tone Database, execute the command –

New-MailboxDatabase -Name <dial tone database name> -EdbFilePath <enter full EDB file location path>

b. To reset user mailboxes hosted on the database being recovered, execute command –

Get-Mailbox -Database <database name> | Set-Mailbox -Database <dial tone database name>

c. To mount Dial Tone database so that client computers can access the database, send and receive the messages, execute the command –

Mount-Database -Identity <dial tone database name>

d. To create a recovery database, execute the command –

New-MailboxDatabase -Recovery -Name < recovery database name> -Server <server name>


To create another recovery database on another Server, execute the command –

New-MailboxDatabase -Recovery -Name <recovery database name> -Server <server name> -EdbFilePath “<full EDB file path location>” -LogFolderPath “<full log folder path location>”

e. Once the data is copied to the Recovery database, copy the log files from the failed database to the recovery database log folder so that they can be played against the restored database.

First, mount the recovery database and then dismount it, execute the commands as –

Mount-Database -Identity <recovery database name>

Dismount-Database -Identity <recovery database name>

f. After dismounting the recovery database, move the current database and log files residing in the recovery database folder to another secured location.

Info: This step is a preparation step to replace the recovered database with Dial Tone Database.

g. Dismount the Dial Tone Database, execute the command –

Dismount-Database -Identity <dial tone database name>

h. Move the database and log files from the Dial Tone database to the Recovery Database folder.

i. Move the database and log files from the secured location to Dial Tone database folder.

Mount the Dial Tone database again, execute the command –

Mount-Database -Identity <dial tone database name>

Users can access the original database and can send or receive messages.

j. Mount the Recovery Database, execute the command –

Mount-Database -Identity <recovery database name>

k. To export data from the Recovery database to recovered database, execute the commands –

$mailboxes = Get-Mailbox -Database <dial tone database name>

$mailboxes | %{ New-MailboxRestoreRequest -SourceStoreMailbox $_.ExchangeGuid -SourceDatabase <recovery database name> -TargetMailbox $_ }

l. Dismount and remove the Recovery database, execute the command –

Dismount-Database -Identity <recovery database name>

Remove-MailboxDatabase -Identity <recovery database name>


To verify that your mailbox has successfully been moved, open the mailbox MS Outlook and Outlook for Web and check messages.

Limitations of Dial Tone Recovery Process using Exchange Management Shell

  • Dial Tone recovery using Exchange Management Shell is a complicated task.
  • Requires technical understanding of Exchange Management Shell.

Steps to perform Dial Tone Recovery on a Single Server

The following screen shows the Exchange Server database in dismounted state.

Guide to Perform Dial Tone Recovery in Exchange Server

Pre-requisite to perform Dial Tone Recovery:

Ensure that the user account has Schema Admin Level permissions on mailboxes.

Steps to Replace the failed Database by a Dial Tone Database (empty database):

1. Login to Exchange Server with Administrator (Schema Admin rights) level profile.
2. Press Win+R, type services.msc, then press ‘Enter’ or click ‘OK’.

Perform Dial Tone Recovery in Exchange Server

3. Stop all three services:

a. Microsoft Exchange Search Service.

b. Microsoft Exchange Search Host Controller Service.

c. Microsoft Exchange Information Store Service.

Manual Guide to Perform Dial Tone Recovery in Exchange Server

4. Navigate to the corrupt Exchange database EDB folder location.

a. Rename the EDB folder name to NAME_old
b. Rename log folder name to NAME_Logs_old

Dial Tone Recovery in Exchange Server

In case, if the EDB folder name is TestEdbToPst, rename it to TestEdbToPst_old.

Guide to Perform Dial Tone Recovery in Exchange Server

5. Start all three stopped services:

a. Microsoft Exchange Information Store Service.
b. Microsoft Exchange Search Host Controller Service.
c. Microsoft Exchange Search Service.

6. Open Exchange Admin Center and mount the database. A warning message appears, click OK to create an empty database.

Dial Tone Recovery in Exchange Server

7. This process creates a new Dial Tone database with the same name.

Manual Steps for Dial Tone Recovery

The empty database will be mounted with all the mailboxes present in the corrupt EDB file.

The following screen shows the Exchange Server database in mounted state.

Dial Tone Recovery Process

A prompt message appears asking users to restart the Microsoft Outlook application on the computer system.

Also, users get a pop-message to use a temporary mailbox for sending and receiving emails when Outlook restarts.

Step by step guide

The temporary mailbox allows maintaining business continuity till the moment the Exchange database is repaired.

Use Professional Solution Like Regain Exchange EDB Recovery Software

Regain Exchange EDB Recovery software restores corrupt or damaged Exchange Server mailboxes. The software recovers accidentally lost or deleted offline EDB mailboxes. The tool repairs corrupt .EDB file and restore deleted or lost emails from the Exchange Server database.

Free Download100% Secure Buy NowPrice: $89

Eminent Features of Exchange EDB Recovery Software

  • Exports/migrates offline and online Exchange EDB mailbox to Outlook PST file.
  • Extracts single or multiple mailboxes as per your need.
  • Converts Exchange Public and Private folders to Office 365 or PST format.
  • Migrates Exchange Server mailbox data from one Server to another server.
  • No file size limit to Convert EDB to PST file.
  • Saves converted emails into PST, EML, EMLX, MSG, MBOX, PDF, VCF, HTML, and MHTML file formats.
  • Displays preview of mailboxes before conversion.
  • Maintains folder hierarchy, integrity, and formatting of emails.
  • Integrated with an inbuilt split option to save a large EDB file to multiple small PST files without any data loss.
  • Allows filtering of EDB files based on date range before migrating them to any other format.
  • Offers a self-descriptive graphical user interface.
  • Compatible with all versions of MS Outlook, Windows Server, and Exchange Server.
  • Available as free to download the trial version.


This article discusses the Exchange Database .EDB files and reasons for corruption .EDB files. Then we discussed Dial Tone Recovery and the methods to perform the Dial Tone Recovery. The Dial Tone Recovery process using Exchange Management Shell is a complicated task and needs deep technical understanding to perform the process.

In the end, we recommend using a third-party Exchange recovery software to repair the corrupt or damaged Exchange database.EDB files. Download the free trial version of Exchange EDB recovery software that saves 30 items per folder.

Author: Deepika Singh

My self Deepika Singh working as a Technical Writer in Regain Software. Having 4+ years experience in Writing Technical blogs, Manual Guides and Articles. I am working on all Regain Software products.

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