How do I fix the error 'Named Pipes Provider, error 40 - Could not open a connection to' SQL Server'?

Question

I can\'t seem to connect to my database from a site. I get this error:

Named Pipes Provider, error: 40 - Could not open a connection to SQL Server

Answer 1

It's a three step process really after installing SQL Server:

1. Enable Named Pipes SQL Config Manager --> SQL Server Network Consif --> Protocols --> Named Pipes --> Right-click --> Restart

2. Restart the server SQL Config Manager --> SQL Server Services --> SQL Server (SQLEXPRESS) --> Right-click --> Restart

3. Use proper server and instance names (both are needed!) Typically this would be .\SQLEXPRESS, for example see the screenshot from QueryExpress connection dialog.

There you have it.

Answer 2

A thread on MSDN Social, Re: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server, has a pretty decent list of possible issues that are related to your error. You may want to see if any of them could be what you're experiencing.

• Incorrect connection string, such as using SqlExpress
• Named Pipes(NP) was not enabled on the SQL instance
• Remote connection was not enabled
• Server not started, or point to not a real server in your connection string
• Other reasons such as incorrect security context
• try basic connectivity tests between the two machines you are working on

Answer 3

I had this issue but none of the suggestions above fixed it.

I was seeing this issue when I deployed my website to IIS. The fix was to go into advanced settings against the default app pool and change the identity property from the default to Administrator.

Answer 4

in my case, i had a standalone server, i changed the sql server port default port 1433 in configuration manager to some number and restarted the sql serve service to take effect,i was able to connect to the sql server through management studio if i login to the server. but i was not able to connect from my local machine through sql server, i was getting the error:

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and

that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 5)

I checked and verified all the below

-Named pipes/TCP is enabled. -Remote connections are allowed. -Windows Firewall is off -Created an exception for portin Windows Firewall( this was not necessary in my case as the server is in same subnet network). -Enabled everything in SQL Server Configuration Manager.

then i chnaged back the port number to default 1433 and restarted the sql server service, and the issue got resolved and i am able to connect the sql server from my local management studio.

Answer 5

I tried pretty much everything on this page but I had some underlying issues which were actually what needed to be resolved. I was unable to do certain things like open SQL Server Configuration Manager, which ended up being corrupt/missing WMI provider files.

There are lots of tedious ways to resolve this issues according to what I've read, but the tool from tweaking.com was able to remove and replace/repair my WMI (Windows Management Instrumentation) Provider files.

I used to do computer repair and overall the tweaking.com tool really impressed me, and it was suggested from one of the WMI error forum pages I went to.

After I fixed this issue I was able to connect to my SQL db, both locally and remotely.

Hope this helps someone.

Answer 6

If you tried restarting the MSSQLSERVER service, and it did not work, this might be a solution:

If you are using SQLExpress, your server name should be as the following ComputerName\SQLExpress. However, for SQLDeveloper, you do not have to right SQLDeveloper after your ComputerName.