Missing Semicolon After &#xA0 With XmlWriter

Recently, I ran into this error:

Exception thrown in BuildReports: Invalid syntax for a hexadecimal numeric entity reference. Line 175, position 3159.

This exception was thrown when   was converted into &#xA0 with the missing semicolon instead of  

This was random.  Some   got converted correctly with the semicolon; and some got converted with the missing semicolon.

Following this link http://social.msdn.microsoft.com/Forums/en-GB/xmlandnetfx/thread/6216ba7b-9af0-42f3-904d-e2bc330dde58 and this link http://connect.microsoft.com/VisualStudio/feedback/details/590715/xmlwriter-generates-invalid-xml

I was able to fix it with changing the encoding from ASCII to UTF8

XmlWriterSettings settings = new XmlWriterSettings();

settings.Encoding = Encoding.UTF8;