Notice! This page describes the nature of the error using a hypothetical example and not the erroneous data of the input test file. You should however be able to apply this information to your error case.

General description of the error:

The format of the error message: Content is not allowed in prolog.

Error description in schema standard:
                                                              More information about prolog here.

Meaning of the error:  Information not considered as valid prolog is given at the beginning of the file. Prolog is optional and it has to be present before the root tag of the file. If prolog is given, it has to contain version attribute, in addition also encoding and standalone attributes can be given.

Possible causes for this error:

  • Prolog has incorrect content
  • Invalid content given after prolog. Either root tag or comment should be present
  • Invalid content given before prolog. Prolog should be the first thing in the file if given.


?<xml version="1.0" encoding="UTF-8" standalone="no"?> 

Error message: Content is not allowed in prolog.

How to fix: Modify prolog so that attributes version, encoding and optionally standalone are given. Prolog is to be inserted inside opening and closing tags "<", ">" and inside question marks "?", with attribute names separated by spaces.    

<?xml version="1.0" encoding="UTF-8" standalone="no"?>