Missing Microsoft.Data.SqlClient 5.0.0 after patching SharePoint Workflow Manager KB5002750

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Missing Microsoft.Data.SqlClient 5.0.0 after patching SharePoint Workflow Manager KB5002750

Greg Ogle 20

I have a SharePoint 2016 Server farm and I just updated SharePoint Workflow Manager per instruction of latest update - kb5002805. Now the SharePoint Workflow service is inaccessible.

In ULS logs, I see an error from Workflow Service with following error message:
Could not load file or assembly 'Microsoft.Data.SqlClient, Version=5.0.0.0, Culture=neutral, PublicKeyToken=23ec7fc2d6eaa4a5' or one of its dependencies. The system cannot find the file specified.

Any help is appreciated.

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Answer 1

Teddie-D 8,640 Microsoft External Staff Moderator

Hi @Greg Ogle

Thank you for posting your question in the Microsoft Q&A forum.

To fully patch a SharePoint Server, you must install both the language-dependent and language-independent updates. This requirement applies even to servers without additional language packs, since every SharePoint installation includes both components.

There was no language dependent fix released this month (November 2025) and the latest language dependent fix is KB 5002787. If this is not yet installed on your Farm, you need to install it together with the language independent fix (KB5002805).
After installing the fixes, you need to run the SharePoint 2016 Products Configuration Wizard on each machine in the farm.
You can read more at November 2025 CU for SharePoint Server 2016 is available for download – Stefan Goßner.

Some environments may encounter issues after patching due to missing assemblies such as Microsoft.Data.SqlClient version 5.0.0. This dependency was introduced by recent Workflow Manager updates. To resolve this, either:

-Install the latest Workflow Manager update and run the Workflow Manager Configuration Wizard, or

-Manually register the missing assemblies such as Microsoft.Data.SqlClient in the GAC.
You may take this link as a reference Trending Issue: System.Memory.dll missing after installing August 2025 CU for SharePoint Workflow M…
Note: Microsoft is providing this information as a convenience to you. These sites are not controlled by Microsoft, and Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. Please ensure that you fully understand the risks before using any suggestions from the above link.

I hope this helps.

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Teddie-D 8,640 Reputation points Microsoft External Staff Moderator

2025-11-27T06:21:32.1733333+00:00

Hi @Greg Ogle
I wanted to follow up and ensure the information provided was useful to you. If you have any new updates or further inquiries, please let me know. Thank you!
Teddie-D 8,640 Reputation points Microsoft External Staff Moderator

2025-12-01T06:11:24.2866667+00:00

Hi @Greg Ogle
May I know if you have got any chance to check my answer? If you need further assistance, please feel free to let me know. Warm thanks!
Greg Ogle 20 Reputation points

2025-12-04T16:08:04.3166667+00:00

So, I did install the previous language pack KB 5002787 and the WF update. I had not yet run Workflow Manager Configuration Wizard, which would not run till I ran the PowerShell to GacInstall the assemblies.

So those, seemed to run okay, however I'm getting an exception when the WorkflowServiceBackend tries to start:
Service cannot be started. System.MissingMethodException: Method not found: 'Boolean Microsoft.Workflow.Common.SqlQueryExecutor.IsSqlExceptionTransient(Microsoft.Data.SqlClient.SqlException)'.

at Microsoft.Workflow.Management.ExecuteSqlAsyncResult.ShouldRetry(ExecuteSqlAsyncResult self, Exception e, Int32& sqlErrorNumber)

at Microsoft.Workflow.Management.ExecuteSqlAsyncResult.HandleException(Exception exception, Boolean& ignoreExceptionAndComplete)

at Microsoft.Workflow.Common.BackoffRetryAsyncResult.IsolateWithRetry(IAsyncResult result)

at Microsoft.Workflow.Common.BackoffRetryAsyncResult.Start()

at Microsoft.Workflow.Management.ExecuteSqlAsyncResult..ctor(Nullable`1 maxRetryTime, SqlOperationContext context, SqlCommand command, String connectionString, Object userState, EventTraceActivity traceId, AsyncCallback callback, Object state)

at Microsoft.Workflow.Management.SqlConfigProvider.BeginGetConfiguration(TimeSpan maxWaitTime, AsyncCallback callback, Object state)

at Microsoft.Workflow.Service.Workflow...

This is from Event Viewer, Source=WorkflowServiceBackend

This leads me to believe it is the wrong version of the SQL assembly, but not quite sure.
Teddie-D 8,640 Reputation points Microsoft External Staff Moderator

2025-12-05T12:23:06.26+00:00

Hi @Greg Ogle

The MissingMethodException confirms that Workflow Manager is loading a Microsoft.Data.SqlClient binary that does not match the validated build it was tested against. Workflow Manager expects AssemblyVersion 5.0.0.0, and when a different binary is loaded, runtime binary incompatibility occurs and the call fails.

Here are some steps you may try:

-Ensure all Workflow Manager nodes and SharePoint servers run the same SPWFM server and client CU. After patching, run Workflow Manager Configuration Wizard > Upgrade Workflow Manager Farm.

-Remove all other Microsoft.Data.SqlClient versions from the GAC and do not place DLLs in the Workflow Manager bin folder.

-Install the validated dependency set into the GAC as mentioned in the previous link.

-Restart WorkflowServiceBackend and re-run the Configuration Wizard.

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Missing Microsoft.Data.SqlClient 5.0.0 after patching SharePoint Workflow Manager KB5002750

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