This is a reposting of an article Chris Roehrich originally wrote on my Developing for Dynamics GP blog.
I am going to go over the steps to find and resolve invalid data characters in Dynamics GP that cause GP Web Services exceptions. A common process of “copying and pasting” a block of text from an external program into the Note window for a Dynamics GP record or an import routine directly to the SQL tables can cause Dynamics GP Web Service to throw an error. When using a .Net application that does a GetSalesOrderByKey error, you may see something like this:
“The application encountered an unhandled system exception. Contact your system administrator for details.”