Xml file that generated by xslt macro is started with an illegal character

I use xslt macro to generate another xml file. the file is started with an illegal character. the character is unvisible.
The file to generate new xsl file(see the following link because this place can’t post it rightly):
http://issues.umbraco.org/issue/U4-8075

By using above method, I can generated one xml content. then save the content as a xml file. but the file can’t be parsed because it is started with an illegal character.


This is a companion discussion topic for the original entry at https://our.umbraco.com/forum/75437-xml-file-that-generated-by-xslt-macro-is-started-with-an-illegal-character