Recently I came across a situation where a user was trying to export a SharePoint Performance Point dashboard data to Excel and was getting the Duplicate Header Received error.
Duplicate headers received from server
I looked into the PerformancePoint dashboard and used the export to Excel option.
I was able to export the data to excel and view it in there.
Under one instance, when I used ‘Export to Excel’ option, the file download dialog box showed an extremely long file name with lots of special characters.
It turns out to be the user was using the Chrome browser instead of Internet Explorer. The error is specific to Chrome as other browsers ignore the duplicate headers.
Enclosing the file names in ” ” or using underscore instead of spaces or comma (,) is one solution.
Read the following articles for little mode details on the issue.