Test connection failed because of an error in initializing provider. The given key was not present in the dictionary.

Question

Test connection failed because of an error in initializing provider. The given key was not present in the dictionary.

SB 5

I am getting this error VS2022 and VS2026 when tried to create a connection from ssis project with connection manager. SQL server version is Microsoft SQL Server 2022 (RTM-GDR) (KB5073031) - 16.0.1165.1 (X64) Nov 24 2025 19:08:45.

It was working well with the previous version of SQL server. I have tried all options like Trust Server certificate, encryption false etc. Tried with Oledb driver for sql server 19, 18 etc

thanks

Suresh.

Deepesh Dhake 85 Reputation points

2026-06-05T12:27:36.9366667+00:00

Could you paste the exact error text?

2 answers

Your answer

Deepesh Dhake 85 Reputation points

2026-06-05T12:27:36.9366667+00:00

Could you paste the exact error text?

Answer 1

Deepesh Dhake 85

This error is a client-side provider mismatch, not your SQL Server or your TLS settings. "The given key was not present in the dictionary" is the SSIS designer failing to load a provider, which is why changing Encrypt/TrustServerCertificate did nothing .

You can try:

Uninstall every "Microsoft OLE DB Driver for SQL Server" entry in Programs and Features (18 and 19), then install a single current MSOLEDBSQL 19, making sure you get both the x64 and x86 builds of the same version. The designer runs as x86, so the x86 build must be present and must match the x64 one.

If this doesn't fix then if you can provide detailed error message then that will be great.

SB 5 Reputation points

2026-06-05T12:44:03.3266667+00:00

When I search for it in Programs and Features I see only 19 listed there. I uninstalled and reinstalled and still getting the same error. How do I get a detailed error? It gives a popup message saying I originally posted. Is there any other way to get a detailed message? Appreciate you taking time to answer!
Erland Sommarskog 134.6K Reputation points MVP Volunteer Moderator

2026-06-05T12:55:40.5666667+00:00

Can you post a screenshot?

The error message sounds like an internal error in Visual Studio, because "dictionary" does not make much sense in the context of connecting. The root case may be due to some connectivity issue, but the real is masked by this error.

By the way, your instance of SQL Server is running the RTM version of 2022 with only security patches. This means that you are missing many fixes and improvements. I would recommend that you download and install the most recent Cumulative Update of SQL 2022 which is CU25. However, it is unlikely that it will resolve the issue you are running into.
Deepesh Dhake 85 Reputation points

2026-06-05T12:59:41.1933333+00:00

The popup itself sometimes has an expander - look for a small arrow, a "Details," "Advanced," or "Technical Information" toggle, or a "Copy" button on the dialog. If it's there, that copies the full KeyNotFoundException stack trace.

If not, check the Visual Studio ActivityLog. Close VS, then start it with logging:

devenv /log

then reproduce the error, close VS, then open the log at:

%APPDATA%\Microsoft\VisualStudio<version>\ActivityLog.xml

Windows Event Viewer also often catches .NET exceptions from VS: Event Viewer then Windows Logs then Application, filter to the time you reproduced it, look for a .NET Runtime or Application Error entry referencing devenv.exe.

Also useful, and faster to check than chasing the trace: open the connection manager and watch when the error fires.

If it throws the moment you open the dialog or click the server dropdown, it's likely the server-enumeration step (SQL Browser / instance list), not the provider.

If it throws only when you click Test Connection or OK, it's the provider/connection path.
SB 5 Reputation points

2026-06-05T13:25:03.98+00:00

Thanks Erland
SB 5 Reputation points

2026-06-05T13:25:49.87+00:00

I selected the image and uploaded and its showing only the text in the image!
SB 5 Reputation points

2026-06-05T13:28:51.4+00:00

sorry my bad

Sorry my bad
Deepesh Dhake 85 Reputation points

2026-06-08T15:40:55.9933333+00:00

Can you try "Microsoft OLE DB Driver for SQL Server" (MSOLEDBSQL)" in Provider drop down box?
SB 5 Reputation points

2026-06-09T18:29:33.6833333+00:00

Deepesh

Yes I tried with that and finally I was able to get it working. Usually VS won't allow unless a specific driver was selected there. With that the error changed to "Cannot load provide....login failed". After putting password I was able to Test the connection successfully. When I close and comeback the password box would be empty even if I set save password. When I hit Test again ( assuming it would pull password from store), it fails. But if I enter password again, it would work. So I am guessing, if I deploy it, it would pull password from file and everything will be fine.

thanks
Erland Sommarskog 134.6K Reputation points MVP Volunteer Moderator

2026-06-09T19:33:37.67+00:00

Great to hear that you got it working!

It would be customary if you would accept Deepesh's initial post as the Answer. If you would rather would prefer to accept any posts posted as the comments as the answer, please let us know. As a moderator, I can rearrange the thread.
Lakshmi Narayana Garikapati 1,330 Reputation points Microsoft External Staff Moderator

2026-06-11T05:26:11.6366667+00:00

Hi @SB ,

Thank you for reaching out to the SQL Q&A Forum, for sharing the workaround and confirming that the issues have been resolved.

@Deepesh Dhake ,

@Erland Sommarskog appreciate your prompt response.

Thanks,

Lakshmi.

Answer 2

The error "Test connection failed because of an error in initializing provider. The given key was not present in the dictionary" when testing an SSIS OLE DB connection is a known issue in SQL Server 2016 SSIS after certain CUs, and is fixed by installing specific cumulative updates.

From the available information, the documented fix is:

Install the cumulative update that contains the fix for this error.
- For SQL Server 2016, the fix is in:
  - Cumulative Update 6 for SQL Server 2016 SP2, or
  - Cumulative Update 14 for SQL Server 2016 SP1.
After applying the appropriate CU, retry the Preview/Test Connection in the CDC Source / OLE DB connection manager.

The context does not provide a corresponding KB for SQL Server 2022, but the pattern is that this specific dictionary-key error in SSIS design-time components is resolved by applying the CU that contains the fix.

References:

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Test connection failed because of an error in initializing provider. The given key was not present in the dictionary.

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