I don't understand :

I've installed sql server 2008 R2. the installation process asked me for the desired instance name , so I wrote: MSSQLSERVER.

after the installation , running Setup Discovery Report does shows me the instance name :

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I've also installed all the service packs.

Also , all the services are up :

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Also , all the ports are open ( tcp:1433 + udp :1434)

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Also , Named pipes are on : enter image description here

So , where is the problem ?

I'm unable to connect via the instance name : enter image description here

Also unable with :

user\MSSQLSERVER where user is the computer name.

Also unable with : .\MSSQLSERVER

But (weird) :

Those 3 do work :

  • user ( "user" is my machine name)
  • (local)
  • .

Question :

why I can't use my instance name to connect to my sql server ?

Related info :

After connecting via one of the 3 who work , I run a helpful info :

enter image description here


You selected the default instance name as the name of your instance.

Instance Configuration

"If you specify MSSQLServer for the instance name, a default instance will be created. For SQL Server Express, if you specify SQLExpress for the instance name, a default instance will be created."

To connect to the default instance you don't specify the instance name, only the server name.

  • Thanks. and what If I choose "lala" as instance name ? would then I be able to cennect via ".\lala" ? – Royi Namir Apr 28 '13 at 19:07
  • 2
    @RoyiNamir yes, if you connect from the computer where SQL Server is installed. Otherwise you need to specify the computer name instead of .. Something like servername\instancename. – Mikael Eriksson Apr 28 '13 at 19:14
  • @RoyiNamir you are welcome. – Mikael Eriksson Apr 28 '13 at 19:26

Use below query to find exact instace name

( Value nvarchar(100),
 InstanceNames nvarchar(100),
 Data nvarchar(100))

Insert into @GetInstances
EXECUTE xp_regread
  @rootkey = 'HKEY_LOCAL_MACHINE',
  @key = 'SOFTWARE\Microsoft\Microsoft SQL Server',
  @value_name = 'InstalledInstances'

Select InstanceNames from @GetInstances 
  • 1
    This barely answers the question. – Tom V Feb 23 '17 at 10:31

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