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sql-server-properties-startup-parameters-tab.md

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title SQL Server Properties (Startup Parameters Tab)
description Use the Startup Parameters tab of the SQL Server Properties dialog box to add or remove startup parameters, which can affect Database Engine performance.
author rwestMSFT
ms.author randolphwest
ms.date 12/15/2025
ms.service sql
ms.subservice tools-other
ms.topic ui-reference
ms.collection
data-tools
monikerRange >=sql-server-2016

SQL Server Properties (Startup Parameters tab)

[!INCLUDE SQL Server Windows Only]

Use this dialog box to add or remove startup parameters for the [!INCLUDE ssDE]. Startup parameters can have a large effect on the [!INCLUDE ssDE] performance. Before adding or changing startup parameters, see Database Engine Service startup options.

Options

Specify a startup parameter

To add a parameter, type the parameter, and then select 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 select Update.

Existing parameters

To remove a parameter, select a parameter, and then select Remove.

Parameter format

Don't enter a separator between parameters. [!INCLUDE ssNoVersion] Configuration Manager automatically adds the separator. [!INCLUDE ssNoVersion] Configuration Manager enforces the following parameter requirements.

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

  • All startup parameters start with a hyphen (-), 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 [!INCLUDE ssNoVersion] error log files.

If the file path parameters are incorrect, [!INCLUDE ssNoVersion] might not start.

For more information about how to move the master database, see Move system databases.

Optional parameters

All of the supported startup parameters are described in Database Engine Service startup options. A startup parameter of -T<trace#> indicates that an instance of [!INCLUDE ssNoVersion] 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 Set trace flags with DBCC TRACEON.

Caution

You might see additional undocumented startup parameters and trace flags described online. 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. Don't use undocumented parameters unless directed by Microsoft Customer Support Services.

The following list describes some common optional parameters.

Parameter Short description More information
-m Starts an instance of [!INCLUDE ssNoVersion] in single-user mode. Single-user mode for SQL Server
-T1204 Returns the resources and types of locks participating in a deadlock and also the current command affected. Trace flag 1204
-T1224 Disables lock escalation based on the number of locks.

[!INCLUDE sssql25-md] introduces Optimized locking instead.		 Trace flag 1224
-T3608 Prevents [!INCLUDE ssNoVersion] from automatically starting and recovering any database except the master database. Trace flag 3608
-T7806 Enables a dedicated administrator connection (DAC) on [!INCLUDE ssExpress]. Trace flag 7806

Caution

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

Permissions

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 [!INCLUDE ssNoVersion], if the [!INCLUDE ssDE] is configured to run under a domain account.

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