SharePoint Excel Services MultipleRequestsOnSession – An operation is already being processed in this session. Only one operation can be processed in a session at a time.

In this post, you’ll learn about the error message “MultipleRequestsOnSession – An operation is already being processed in this session. Only one operation can be processed in a session at a time.” that you usually receive when working eith the Excel Services in SharePoint.

When working with SharePoint Excel Services, there are error codes that are generated in the SOAP exception when the errors occur in the Excel Services. You can use the SubCode property that is available in the SoapException class to identity these error codes and troubleshoot the issue.

Error Message

MultipleRequestsOnSession – An operation is already being processed in this session. Only one operation can be processed in a session at a time.

Reason for the Error

Multiple requests have been issued on the same session. A session can only process one request at a time (with a few exceptions).

Solution

Try performing the operation again.