How can I get a list of installed SQL Server instances?

Today we’ll talk about how we can get a list of locally installed SQL Server instances on a system.   This information is stored in the registry at the following ___location:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\Instance Names\SQL

EDIT:

If you are looking for 32 bit instances on a 64 bit OS, you will need to look here:

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Microsoft SQL Server\Instance Names\SQL

All we need to do is query this registry key to get the list of instances installed on a machine. On my personal machine, I have the following instances installed:

SQLEXPRESS
MSSQLSERVER
CRASH
DEBUG
MICROSOFT##SSEE
SQL2005  

Below are a few ways we can get this information for 64 bit instances on 64 bit Windows:

Command shell “reg.exe” utility:

reg query "HKLM\Software\Microsoft\Microsoft SQL Server\Instance Names\SQL"

In PowerShell:

Get-ItemProperty 'HKLM:\Software\Microsoft\Microsoft SQL Server\Instance Names\SQL'

In .NET:

RegistryKey baseKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64);
RegistryKey key = baseKey.OpenSubKey(@"SOFTWARE\Microsoft\Microsoft SQL Server\Instance Names\SQL");

foreach (string s in key.GetValueNames())
{
MessageBox.Show(s);
}

key.Close();
baseKey.Close();

If you need to read the registry from another computer, then the RegistryKey class has a “OpenRemoteBaseKey” static method that you can use. 

- Jay

Comments

• Anonymous
  October 11, 2011
  What's the situation when there are 64-bit and 32-bit on an x64 system? Do we query WoW6432 for 32-bit and native registry for 64-bit?
• Anonymous
  October 11, 2011
  @Phil - thanks for catching that.  I should have put this is for 64 bit instances - running on 64 bit Windows.  If you are looking for 32 bit instances on a 64 bit machine, you'll need to look here:HKEY_LOCAL_MACHINESOFTWAREWow6432NodeMicrosoftMicrosoft SQL ServerInstance NamesSQLI edited the post to note that.
• Anonymous
  November 11, 2012
  this is good, thanks Jay
• Anonymous
  March 01, 2013
  Thank you for answering the question first time, correctly.
• Anonymous
  October 18, 2013
  it just works for SQL2005 or higher... not for SQL2000
• Anonymous
  November 13, 2013
  That gets all installed instances; is there a way to show which of those are active? I'm running an active-active SQL2008r2 cluster and it'd be handy to know when both instances are running on a single node.