I have a strange issue today. 

In my report, I am trying to create a parameter to select a specific salesman. I have joined the salesperson table to my service order table and have the following filter set 

SalesPerson.SalesPersonCD  Equal @Salesman  Or

@Salesman IsNull

My parameter is setup as follows

When I set a default value to the salesman parameter and then click preview, it works as it should and there are no errors. However, when I save to server and run the report, it gives me the following error:

I don’t understand, the parameter selector is the exact same syntax as what it is filtering the report by. I have never had this error before. I understand how to fix it when there are issues translating from string to datetime or string to int for example, but I have never had an issue going string to uniqueidentifier. I didn’t even realize those were separate syntaxes to be honest.