I have GridAttachmentColumn in a DetailTable of a RadGrid that is Ajaxified. I get following error when clicking 'Download':
"Error: Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed. Common causes for this error are when the response is modified by calls to Response.Write(), response filters, HttpModules, or server trace is enabled."
This error does not happen if the GridAttachmentColumn is inside the main table. But unfortunately I can't have it in the main table, it has to be in DetailTable.