The ExpressionTranslationBuildTask task failed unexpectedly SharePoint Visual Studio Workflow Error

This SharePoint workflow tutorial, we will discuss how to fix an error The ExpressionTranslationBuildTask task failed unexpectedly which comes while developing a workflow using visual studio 2015 for SharePoint online sites.

In one of our requirement, we have developed a workflow using visual studio 2015 for SharePoint Online. Here we were trying to send email using Email workflow activity.

In that activity, we have declared a variable and we were trying to assign it into the To field of the email. But it gave us error like:

The “ExpressionTranslationBuildTask” task failed unexpectedly….

The ExpressionTranslationBuildTask task failed unexpectedly

The solution to resolve the issue was to change the data type of the variable from String to Collection<T> type.

We have declared the variable like below:

To change the variable type, click on the variable type and then select Browse for Types… like below:

And then choose the System.Collections.ObjectModelCollection<T> type like below:

Now the error will not come.

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This tutorial helps to fix error The ExpressionTranslationBuildTask task failed unexpectedly which comes while developing visual studio workflow.