How to Resolve the 'The processing instruction target matching 'xX[lL]' is not allowed' XML Error?

Error: "The processing instruction target matching "xX[lL]" is not allowed"

This error commonly occurs when an XML declaration appears anywhere but at the beginning of an XML document, contrary to XML specifications. While many parsers may issue similar error messages, this issue is particularly notable with Xerces-based tools.

To resolve this error, thoroughly inspect the XML document for any potential issues:

1. Visible Content Before XML Declaration:
Check for any whitespace characters or other visible content preceding the declaration. Eliminate any such content to ensure the XML declaration is the first visible content.

2. Invisible Content (BOM):
A Byte Order Mark (BOM) is an invisible character that can sometimes appear before the XML declaration. Use appropriate techniques, such as those recommended by the W3C, to remove any BOMs from the document.

3. Stray XML Declarations:
Accidental XML declarations within the document can cause this error. Perform a case-insensitive search for

By carefully addressing these potential issues, you can resolve the error and ensure that your XSLT page runs without any problems.

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