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Microsoft KB Archive/171225

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Knowledge Base

PRB: Unable to Connect to Stand-Alone SQL Server

Article ID: 171225

Article Last Modified on 11/14/2003


  • Microsoft SQL Server 4.21a Standard Edition
  • Microsoft SQL Server 6.0 Standard Edition
  • Microsoft SQL Server 6.5 Standard Edition

This article was previously published under Q171225


Attempting to connect to SQL Server on a stand-alone computer or a laptop computer with no network connections may fail with the following error message:

Unable to connect: SQL Server is unavailable or does not exist.
Specified SQL server not found.

This error may occur during installation, or during subsequent attempts to connect to the server.


By default, client connections to SQL Server are made over a network protocol. Without a simulated network connection, the connection to SQL Server cannot be made unless a local named pipes connection is forced.


To simulate network connectivity, install the MS Loopback Adapter according to the following steps for the version of Windows NT Server you are using:

Windows NT Server 4.0:

  1. In Control Panel Network, click the Adapters tab and then click Add.
  2. From the list, select the MS Loopback Adapter.

Windows NT Server 3.x:

  1. In Control Panel Network, click Add Adapter.
  2. From the Network Adapter Card menu, select MS Loopback Adapter.

The Windows NT installation CD is required. If you are using the IPX/SPX protocol, a frame type of 802.3 is the default, and should be accepted. For TCP/IP configurations, specify an IP address of and a subnet mask of You will need to restart Windows NT Server for this change to become effective.

If you are unable to install the MS Loopback Adapter, shut down the workstation service (through Control Panel Services) to force a local named pipes connection to be made during installation. Be aware that this approach extends the installation time considerably. After the server is installed, you can restart the workstation services. For subsequent connections, you can force a local named pipes connection to the server by not specifying the server name at connection time. You may also specify ".", or "(local)" as the server name in ISQL/w and in SQL Enterprise Manager when registering the server. However, when trying to install a service pack for SQL Server you will get the following error message:

"The entered password failed verification Please check you password."

In order to successfully install the service pack you will need to create an advanced entry in the client configuration utility, specifying ".", or "(local)" as the connection string for the server name.

For 16-bit applications, the MS Loopback Adapter is required. For more information, see the following article in the Microsoft Knowledge Base:

130745 : Connecting to Standalone SQL Server Using 16-bit Apps.

If you have removed all network support and stopped the workstation service, but still continue to get the Unable to connect error, do the following:

  1. From a command prompt, type the following:

    cd \sql\binn
    setup /t RegistryRebuild = On

    NOTE: For SQL Server version 6.0, you can use either = On or = True for the Setup command line.

    NOTE: For SQL Server version 6.5, the default directory is \Mssql\Binn.

    NOTE: Be sure to type the Setup command exactly as indicated, including capitalization. There must be a space on both sides of the equal sign.
  2. Build your master. When the retry dialog appears, task out and setup an advanced client config as the server name, named pipes, ".". Then press the retry button in SQL Server setup.
  3. Once you have a valid master built, run the upgrade to ensure all scripts are active. This may again encounter the login error. Reset the client configuration advanced entry.

Additional query words: FAQ notebook stand-alone fails

Keywords: kbbug kbnetwork kbsetup kbprb kbsqlserv650bug KB171225