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 :

enter image description here

I've also installed all the service packs.

Also , all the services are up :

enter image description here

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

enter image description here

enter image description here

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

2 Answers 2


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, 2013 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. Apr 28, 2013 at 19:14
  • @RoyiNamir you are welcome. Apr 28, 2013 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, 2017 at 10:31

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.