I recently enabled DAC and noticed this error when first trying to connect with object explorer in SSMS:

Cannot connect to admin:servername

Dedicated administrator connections are not supported via SSMS as it establishes multiple connections by design. (Microsoft.SqlServer.Management.SqlStudio.Explorer)

It works fine via sqlcmd or just doing File>New>Database Engine Query.

My question is, how many default connections are made when you connect to a server in Object Explorer? I would guess if you have it configured to spawn a new query window that would be another connection? The SQL Server Agent?

I understand this answer: Is it possible to estabilish Dedicated Administrator Connection (DAC) using SSMS? but I was just curious what connections are made by default.


  • 2
    There is also a background connection for Intellisense queries. – Dan Guzman Nov 5 '19 at 13:38
  • Oh wow, I had no idea. Thanks! – Ross Nov 5 '19 at 13:39
  • I suspect this might vary based on which version of SSMS you're using as well. The last few versions (17, 18) have optimized the SMO usage quite a bit, for example. But it's definitely > 1 – LowlyDBA - John M Nov 5 '19 at 15:19
  • FWIW, the drop-down for databases in a query windows doesn't work either when in single user or DAC. Not sure if it uses intellisense to its own connection. A trace can of course find out, but I can imagine what different actions can spawn their own sessions, hence the answer to the question would be "it depends on what you do in OE". – Tibor Karaszi Nov 6 '19 at 10:41

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