Yesterday, on a whim I launched SQL Profiler on my laptop. I had not launched the Profiler client for a long time, especially given its deprecated status. All the more, with the recent introduction of XE Profiler within SSMS 17.3, there is even lesser motivation to use the old standalone Profiler. But still... I launched Profiler yesterday and when I tried to connect to my SQL Server 2017 instance, this is what I got:
When you look at the detailed exception information provided this is what we get:
Class not registered (pfutil) ------------------------------ Program Location: at CProfilerSqlDbConnection.Open() at Microsoft.SqlServer.Management.UI.ConnectionDlg.Connector.ConnectorThread()
While Profiler is deprecated, it should certainly not throw errors like this. So I decided to take a closer look. With some debugging I figured that somehow Profiler is not able to create a OLEDB connection using the SQLNCLI11 provider. This triggered some 'connections' in my mind, because I remembered that I had recently had to uninstall and reinstall the same for usage with the RML Utilities for SQL Server. I figured that somehow those steps might have caused some COM registration issues with SQLNCLI11.DLL. So I executed the following command from an administrative command prompt:
regsvr32 C:WINDOWSsystem32sqlncli11.dll
Voila! That fixed the issue. So in the rare event that you are still using Profiler and happen to run into this even more rare error, I hope the simple step to register SQLNCLI11 will help you recover quickly!