When running on a Windows 7 CHN system, Vivado IP Catalog creates an invalid character in front of the first line of *_sdk.xml.
When trying to import the XML file in SDK, the error message "Invalid Hardware Specification XML file." is received.
This can be worked around by deleting the first letter of the *_sdk.xml file or rerunning "Generate Output Products ..." in a Windows 7 EN environment.
This issue is fixed in Vivado 2014.3.