Msmdpump.dll OLAP data pump is throwing a 500 error


How do I resolve this issue with requests to msmdpump.dll for connections to SQL Server Analysis Services? I am receiving a 500 Error from the IsapiModule.

On a Windows Server 2012 R2 machine, with IIS 8.5, I have setup the OLAP data pump (msmdpump.dll), using the following instructions:

  • The application pool is configured for .NET CLR v4.0, with Classic Managed pipeline mode. The identity is set to a local service account. (I have also tried a domain account, and I have tried making the local user an Administrator).
  • I've created an application under the Default Web Site, called OLAP, with an IsapiModule, as per the MSDN article.

IIS setup for OLAP data pump

As far as I can tell (and I've double and triple checked), everything is configured as laid out in the MSDN article. Also, compared to another server where I have this setup (on a different network), it is essentially the same.

When I request http://localhost/OLAP/msmdpump.dll in a browser on that machine, I receive a 500 Internal Server Error. The error indicates that it is trying to use the OLAP handler that I created. This is not the same error that I would normally expect when doing a GET request to msmdpump.dll. The normal error for a straight GET, when everything is working correctly, is sent back in a SOAP envelope. In my case, the request does not appear to ever be processed by msmdpump.dll.

500 Internal Server Error via browser:

(see below for full screenshot)

Module   IsapiModule 
Notification   ExecuteRequestHandler 
Handler   OLAP 
Error Code   0x8007007e 

Requested URL   http://localhost:80/OLAP/msmdpump.dll 
Physical Path   C:\inetpub\wwwroot\OLAP\msmdpump.dll 
Logon Method   Anonymous 
Logon User   Anonymous 

500 Internal Server Error via SSMS connection:

I also receive an error when trying to connect to the data pump via SQL Server Management Studio:

SSMS OLAP connection 500 error

Screenshot of the 500 error in the browser:

IIS OLAP data pump IsapiModule 500 error

One appreciable difference between the machine I'm setting up, and the server where the data pump already works, is that there are a few more roles setup on the new server.

The problem server includes:

  • .NET Extensibility 4.5
  • ASP.NET 4.5

While the other machine (where the data pump works), does not include those roles. Would the presence of ASP.NET 4.5 or .NET Extensibility 4.5 cause an issue with IIS serving requests for this IsapiModule?

asked on Stack Overflow Mar 25, 2016 by Seibar • edited Mar 25, 2016 by Seibar

1 Answer


You should probably disable Anonymous Authentication on IIS

answered on Stack Overflow Nov 13, 2019 by Marek Lesko

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