SQL SERVER – Start SQL Server Instance in Single User Mode

There are certain situation when user wants to start SQL Server Engine in “single user” mode from the start up.

To start SQL Server in single user mode is very simple procedure as displayed below.

Go to SQL Server Configuration Manager and click on  SQL Server 2005 Services. Click on desired SQL Server instance and right click go to properties. On the Advance table enter param ‘-m;‘ before existing params in Startup Parameters box.

Make sure that you entered semi-comma after -m. Once that is completed, restart SQL Server services to take this in effect. Once this is done, now you will be only able to connect SQL Server using sqlcmd.

SQL SERVER - Start SQL Server Instance in Single User Mode singleuser

Make sure to remove newly added params after required work is completed to restart it in multi user mode.

Reference : Pinal Dave (https://blog.sqlauthority.com)

SQL Scripts, SQL Server Management Studio, SQL Server Security, SQL Utility
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56 Comments. Leave new

  • should be sp_addsrvrolemember intead of sp_addsrvrolememEber

  • I tried 10 solutions for this problem, none of them worked except yours.

    Thank you very much.

  • hi
    how can start my sql server 2008 r2 in single user mode

  • Thanks for this article! Saved me a bunch of time reinstalling & attaching databases!

  • Chandrashekar M S
    November 22, 2013 3:45 pm


    I’m not able to change the start up parameter in MSSQL 2012 server, getting error as “The Parameter is Invalid”. Not getting where I’m wrong here, earlier several times I had tried this.

    Parameter :

    -m;-dC:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\DATA\master.mdf

    Please help me.

  • Hi Dave just wanted to say thanks a million for all the incredible advise you always give to the SQL community. I know this comment is 2 years after the original one but i just wanted to make a comment on this.
    1. after the server is started in single user mode make sure all other sql services like reporting services etc. are stopped or it will tell you that another user is already connected.
    2. using SQLCMD -S from the command prompt I found is easiest for me to connect then i just use TSQL commands to fix the issues

  • Thanks for your wonderful post. Unfortunately, I run into some problem. I have a few Server Instances on the same server. Not sure it was the culprit or not. However, after adding -m; into the Startup Parameters and restarted successfully, I am not able to connect to the database server using SQLCMD. Is there anything I need to check ?

  • Hi
    I have closed sql server management studio 2012 with stop mood how can I start it ??

  • Hi,
    If in Advance Tab- Startup Parameters box contain is disabled,then how to enabled it ??

    Please replay.
    Thanks in Avvance.


  • If you’re receiving an error from sqlcmd similar to “”Login failed for user ‘sa’. Reason: Server is in single user mode. Only one administrator can connect at this time.” and have an error message similar to “Script level upgrade for database ‘master’ failed because upgrade step ‘sqlagent100_msdb_upgrade.sql’ ” in the event viewer after you start the service this link might solve your problem: https://support.microsoft.com/en-us/help/2163980/fix-the-sql-server-service-cannot-start-after-you-install-cumulative-u

    Chased this around for hours before figuring it out.

  • When I try this on SQL 2008 and attempt to restart the service, the service crashes on start up. I am not having any luck starting up the service after adding -m; to my parameters.

  • SQL server did not start due to incorrect model file path- Add -T3680 startup parameter in the SQL server service from the SQL server configuration manager and restart the service.Open the command prompt as administrator. From the command prompt type ‘NET START MSSQLSERVER /mSQLCMd’. this would start SQL in single user mode and would only allow connections from SQLCMd. A sysadmin should be able to login from SQLCmd but if you are unable to login check the error logs and see if there are any trace flags that are starting as soon as the service starts.delete other statup parameters (except the master db files and error log parameters) and try to login through SQLCMd. For default instance
    ‘SQLCMD -S . _Usa’ and then change the file path location.

  • Hi,
    I started the instance of SQL Server using CMD.
    What should i do next?
    The last thing visible on CMD is
    2016-01-27 19:46:25.89 spid13s Service Broker manager has started.
    2016-01-27 19:46:25.89 spid6s Recovery is complete. This is an informational
    1 message only. No user action is required.


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