SQL Server Properties (Startup Parameters Tab)

Applies to: SQL Server - Windows only

Use this dialog box to add or remove startup parameters for the Database Engine. Startup parameters can have a large effect on the Database Engine performance. Before adding or changing startup parameters, see the topic "Using the SQL Server Service Startup Options" in SQL Server Books Online.


Specify a startup parameter
To add a parameter, type the parameter, and then click Add.

To modify one of the required parameters, select the parameter in the Existing parameters box, change the values in the Specify a startup parameter box, and then click Update.

Existing parameters
To remove a parameter, select a parameter, and then click Remove.

Parameter Format

Do not enter a separator between parameters. SQL Server Configuration Manager automatically adds the separator. SQL Server Configuration Manager enforces the following parameter requirements.

  • Leading and trailing spaces are trimmed from any startup parameter.

  • All startup parameters start with a - (dash) and the second value is a letter.

Required Parameters

The following parameters are required. They can be changed but not removed.

  • -d is the path of the master.mdf file (the master database data file).

  • -l is the path of the master.ldf file (the master database log file).

  • -e is the path of the SQL Server error log files.


If the file path parameters are incorrect SQL Server might not start.

For more information about how to move the master database, see the topic "Moving System Databases" in SQL Server Books Online.

Optional Parameters

All of the supported startup parameters are described in the topic "Using the SQL Server Service Startup Options," in SQL Server Books Online. A startup parameter of -Ttrace# indicates that an instance of SQL Server should be started with a specified trace flag (trace#) in effect. Trace flags are used to start the server with nonstandard behavior. For more information about trace flags, see the topic "Trace Flags ( Transact-SQL)" in SQL Server Books Online.


You might see additional undocumented startup parameters and trace flags described on the Internet. Undocumented startup parameters and trace flags are created to address uncommon problems or to force certain conditions required for testing. Using undocumented startup parameters can have unexpected results. Do not use undocumented parameters unless directed by Microsoft Customer Support Services.

The following list describes some common optional parameters.

Parameter Short description
-m Starts an instance of SQL Server in single-user mode.
-T1204 Returns the resources and types of locks participating in a deadlock and also the current command affected.
-T1224 Disables lock escalation based on the number of locks.
-T3608 Prevents SQL Server from automatically starting and recovering any database except the master database.
-T7806 Enables a dedicated administrator connection (DAC) on SQL Server Express.


Some optional parameters can change server behavior and may affect performance.


Use of this page is restricted to users who can change the related entries in the registry. This includes the following users.

  • Members of the local administrators group.

  • The domain account that is used by SQL Server, if the Database Engine is configured to run under a domain account.

Books Online References

For additional information about SQL Server startup parameters, see "How to: Configure Server Startup Options ( SQL Server Configuration Manager)" in SQL Server Books Online.