Updated: 4/18/2006

The SQL Server documentation team cannot answer technical support questions, but welcomes your suggestions and comments about this readme documentation. You can quickly and directly send e-mail feedback using the link below. Please send your feedback in English.

To submit written feedback about this document, click here: Submit feedback.


System requirements

The following table lists the prerequisite software and minimum hardware and software requirements for running Microsoft SQL Server 2005 Express Edition (SQL Server Express). To determine if the computer meets the system requirements, from the Start menu, right-click My Computer, and then click Properties. The General tab displays the CPU type and speed, and the amount of installed memory (RAM).

Prerequisite software

Microsoft .NET Framework

Microsoft Internet Explorer 6.0 Service Pack 1 (SP1) or later (prerequisite for .NET Framework)


Minimum: 192 MB

Recommended: 512 MB or higher

Hard Disk space

600 MB free space


Pentium III Compatible or higher

Minimum: 500 MHz

Recommended: 1 GHz or higher

Operating System

Windows Server 2003 SP1

Windows Server 2003 Enterprise Edition SP1

Windows Server 2003 Datacenter Edition SP1

Windows Server 2003 Web Edition SP1

Windows Small Business Server 2003 Standard Edition SP1

Windows Small Business Server 2003 Premium Edition SP1

Windows XP Professional SP2

Windows XP Home Edition SP2

Windows XP Tablet Edition SP2

Windows XP Media Edition SP2

Windows 2000 Professional Edition SP4

Windows 2000 Server Edition SP4

Windows 2000 Advanced Edition SP4

Windows 2000 Datacenter Server Edition SP4

Virtual PC

Virtual Server

There is no support in this release for Windows XP Embedded Edition.


Before You Install SQL Server Express

Before you install Microsoft SQL Server 2005 Express Edition (SQL Server Express), make sure that you install the correct version of .NET Framework associated with SQL Server Express.

SQL Server Express version .NET Framework version

SQL Server 2005 Express Edition 

If you are installing SQL Server 2005 Express Edition, perform the following steps in order:

  1. Uninstall .NET Framework 1.2 and later versions from your computer (versions 1.0 and 1.1 do not have to be uninstalled). Then, install .NET Framework 2.0. from the .NET Framework 2.0 Download Center.

  2. Install SQL Server 2005 Express Edition from the Microsoft Web site.

Using Command Prompt Options to Install SQL Server Express

SQL Server 2005 Express Edition (SQL Server Express) Setup provides a command prompt interface in addition to the graphical user interface. See "Running Setup from the Command Prompt" in SQL Server 2005 Books Online to customize how Setup installs SQL Server Express.

SQL Server Express is a limited edition of SQL Server 2005. The setup experience using the command prompt for SQL Server Express is similar to that of SQL Server 2005.


Modifying SQL Server Express Installed Components

If you install SQL Server Express from the download center on the SQL Server Express Web site, you will use sqlexpr.exe to run Setup. If sqlexpr.exe is run directly without saving to a folder, the temporary directory where the binary files are extracted is deleted after the installation is complete. If you try to modify the SQL Server Express components by using Add or Remove Programs in Control Panel, the Change button looks for a setup directory but cannot find it.

To modify the installed SQL Server Express components, you must download sqlexpr.exe again from the Web site, and save the .exe to a folder. At the command prompt, change the path to the folder where the .exe is stored, and run Setup by using the sqlexpr.exe  –x parameter. You are prompted to select an extraction/installation directory.

When you have extracted the Setup files, you can use the Change button to make modifications to your SQL Server Express installation by specifying the extraction directory when prompted.

This scenario is not true when SQL Server Express is installed as part of Visual Studio 2005 Express. For more information about Visual Studio Express, see Visual Studio 2005 Express Products.


Upgrading MSDE to SQL Server Express

If MDSE was installed with an MSI setup, the existing MSDE instance is upgraded when you install Microsoft SQL Server 2005 Express Edition (SQL Server Express) with the same instance name. Use the Default instance option when you run SQL Server Express Setup. The exception to this is if the version of SQL Server Express you are installing is not the English-language version. Then, the MSDE installation you are upgrading must either be the same language as the SQL Server Express version, or it must be English.   

If MSDE was installed as part of another application that used its own install program, the SQL Server Express installation program does not know about it. In this scenario, the only way to upgrade SQL Server Express is to install SQL Server Express under another instance name. Use the Named Instance option to specify a new instance name when you run SQL Server Express Setup, and then detach the databases from MSDE and attach them to SQL Server Express.  

To know if MSDE was installed as part of another application, in Control Panel, go to Add or Remove Programs. If MSDE does not appear in Add or Remove Programs, it was installed as part of another application. In this scenario, the only way to remove MSDE is to uninstall the application that installed MSDE. In most situations, the application vendor, rather than the application users, handles the upgrade.