Before posting a new bug I want to confirm this. I am reading in graphml.xsd as a Schema to validate against, which has other xsd files that it references located in same folder. Linux x86_64, Python 2.5, lxml 2.2beta4 lxml.etree: (2, 2, -96, 0) libxml used: (2, 6, 32) libxml compiled: (2, 6, 32) libxslt used: (1, 1, 24) libxslt compiled: (1, 1, 24) Code to reproduce error: In [1]: from lxml import etree In [2]: etree.XMLSchema(file="grap graphml+svg.xsd graphml-attributes.xsd graphml-parseinfo.xsd graphml-structure.xsd graphml.dtd graphml.xsd In [2]: s = etree.XMLSchema(file="graphml.xsd") Segmentation fault Schemas can be obtained here: http://graphml.graphdrawing.org/specification.html Loading the others seg faults too. -Chris