Sometimes, when you try to start directory service on MS Exchange Server, following error message is displayed on your computer screen:

Could not start Microsoft Exchange Directory service on \\SERVERNAME Error 2140: An internal Windows NT error occurred

When preceding error message occurs, following events are recorded in the Application log:

Event ID: 109
Source: ESE97
Type: Information
MSExchangeDS (988) the database engine is replaying log file R:\LogFiles\DSAData\edb.log.
Event ID: 110

Source: ESE97
Type: Information
MSExchangeDS (988) the database engine has successfully completed recovery steps.

Event ID: 0
Source: ESE97
Type: Information
MSExchangeDS (988) -510

Event ID: 1166
Source: ESE97
Type: Information
Error -510 has occurred (internal ID 2030148). Contact Microsoft Technical Support for assistance.

Event ID: 1002
Source: ESE97
Type: Information
The Microsoft Exchange Server database (EDB) could not be initialized and returned error -510. Unrecoverable error, the directory can’t continue.

Reason

The error number -510 in the preceding events refers the JET_errLogWriteFail message. This error message generally occurs when the .log file gets damaged.

Solution

Following steps help you to resolve the specified error message:

1. Backup the current database either in offline mode or in online mode.
2. Now, you need to check the consistency of Dir.edb file. You can check the consistency of Dir.edb file by executing the following command:
   eseutil /mh Dir.edb
3. After executing the command check the output to notice the state of Dir.edb file. If the output states the file is consistent then remove all .log files and start the directory service. But, if the Dir.edb file is found inconsistent then restore it from backup.
4. If you restore the Dir.edb file from online backup then replay the transaction logs that are older than the transaction log. But, if you restore the Dir.edb from offline backup then remove the database and transaction log directories and restore the Dir.edb file only.

In case, you do not want to manually perform the recovery process then use Kernel for Exchange Server repair software. While using the Exchange Server Recovery software, you just need to browse the location of the damaged .EDB file and the software will do the rest of the work. Kernel for Exchange Server is a professional Exchange repair and recovery software to rebuild corrupted EDB files. It helps you to repair .EDB file, which has been damaged due to various known and unknown reasons and recover data without any loss. EDB to PST converter software supports almost all versions of Microsoft Exchange Server ranging from Exchange Server 5.0 to Exchange Server 2016.