I have a workflow that is giving unexpected results. The workflow runs when a when an list item is added. It checks and retrieves all attachments on the list item and updates a field with the attachment URL.

The stages I have are broken down into

  • Calling the web service and retrieving the urls
  • Building the string
  • Updating the list item field.

The workflow works fine for one or two attachments. Anything above that throws an error:

Details: An unhandled exception occurred during the execution of the workflow instance. Exception details: System.ApplicationException: HTTP 500 {"Transfer-Encoding":["chunked"],"X-SharePointHealthScore":["0"],"SPClientServiceRequestDuration":["27"],"SPRequestGuid":["f798b4f9-aac5-a604-b579-b27adfad953d"],"request-id":["f798b4f9-aac5-a604-b579-b27adfad953d"],"X-FRAME-OPTIONS":["SAMEORIGIN"],"MicrosoftSharePointTeamServices":[""],"X-Content-Type-Options":["nosniff"],"X-MS-InvokeApp":["1; RequireReadOnly"],"Cache-Control":["max-age=0, private"],"Date":["Thu, 12 Mar 2015 14:17:08 GMT"],"Server":["Microsoft-IIS/8.0"],"X-AspNet-Version":["4.0.30319"],"X-Powered-By":["ASP.NET"]} at Microsoft.Activities.Hosting.Runtime.Subroutine.SubroutineChild.Execute(CodeActivityContext context) at System.Activities.CodeActivity.InternalExecute(ActivityInstance instance, ActivityExecutor executor, BookmarkManager bookmarkManager) at System.Activities.Runtime.ActivityExecutor.ExecuteActivityWorkItem.ExecuteBody(ActivityExecutor executor, BookmarkManager bookmarkManager, Location resultLocation)

It appears to breakdown when assigning the new string variable. I can log the 3rd url. But after I add it to the variable and try to log the new variable I get nothing.

1 Answer 1


So turns out I was using the workflow history list to log the string I was building. On that list the description field is a single line text field, not a multi line. By logging the string to this list with the giant string I was building, I was running over the length of the field which caused my issue.

Also, I found that the maximum string length in sharepoint designer is 255 and will be truncated if it exceeeds that length. To get around this limit I instead updated the multi line list field directly adding one url at a time instead of building out the entire string and then updating the list item field.

https://msdn.microsoft.com/en-us/library/office/dn292551.aspx#bkm_05 https://technet.microsoft.com/en-us/library/cc262787.aspx

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