Microsoft exchange server error 2140

SYMPTOMS
If you try to start the Microsoft Exchange Message Transfer Agent (MTA) service, you may receive the following error message:

Could not start the Microsoft Exchange Message Transfer Agent service on \\ServerName. Error 2140: An internal Windows NT error occurred.

If you try to run the MTA Database Integrity Checker Utility (Mtacheck.exe), you may receive the following error message:

Database contains serious errors and cannot be automatically repaired.
Additionally, you may see the following events in the Application event log of Windows NT Event Viewer:

Event ID: 2152:
Event Type: Warning
Event Source: MSExchangeMTA
Event Category: Operating System
Description:

MSExchangeMTA - A fatal database error occurred, the database recovery operation was not successful and manual correction will be required. Details can be found in the file: drive :\Exchsrvr\Mtadata\.\MTACHECK.OUT\MTACHECK.LOG. Please contact Microsoft Product Support Services. [DB Server MAIN BASE 1 14] (16)

Event ID:2127
Event Type: Warning
Event Source: MSExchangeMTA
Event Category: Operating System
Description:

An MTA database server error was encountered. Error accessing object attribute (AAT) on a Read/Write operation. Filename: drive:\Exchsrvr\Mtadata\.\DB000068.DAT. File operation: 0. Operating system error: 2127. Referenced object: OPEN (00000000 => N/A). Referenced object error 00000000. [0 DB Server OPERATOR 22] (14)

Event ID:2155
Event Type: Warning
Event Source: MSExchangeMTA
Event Category: Internal Processing
Description:

An MTA database server error was encountered. Failed to read attribute information (AAT) for object 01000068. Database server error code: 2127. [DB Server OPERATOR 22 29] (14)

Event: 2187
Source: MTA
Type: Warning
Cat: Internal Processing

Description: An MTA database server error was encountered while attempting to unlock an object which is not locked. Called from MTA. Procedure 460. Object at fault: 06000174. [DB Server DISP:ROUTER 16 58] (14)

Event ID: 2219
Source: MSExchangeMTA
Category: Field Engineering
Description:

The MTA is running recovery on the internal message database because the MTA was not shut down cleanly. This operation may take some time. Status updates will be written to the Windows NT Event Log. [%1 %2 %3 %4] (14)
CAUSE
This issue may occur if incorrect values exist for the location of the MTA database path in the registry.
RESOLUTION
To resolve this behavior, edit the registry to refer to the correct location for the MTA database files. To do so, follow these steps:

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Click Start, and then click Run.
In the Open box, type regedit, and then click OK.
Locate the following registry entry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeMTA\Parameters\MTA Database Path

Double-click the registry entry that you located in step 3, and then type the correct path to the MTA database files in the Value data box. For example, drive:\exchsrvr\mtadata.
Locate the following registry entry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeMTA\Parameters\MTA Run Directory

Double-click the entry that you located in step 5, and then verify that the correct location for the MTA Run Directory is displayed in the Value data box. For example, drive:\exchsrvr\mtadata.
On the Registry menu, click Exit to quit Registry Editor.
NOTE:You can also use Microsoft Exchange Server Performance Optimizer to move the MTA database files. To start Performance Optimizer, click Start, point to Programs, point to Microsoft Exchange, and then click Microsoft Exchange Optimizer. If you want to run Performance Optimizer in verbose mode, follow the steps in the following Microsoft Knowledge Base article: