I was already upgrade my laptop to windows 8.1 preview 64-bit,
I have this only one error when was start my cad application autodesk inventor pro 2014 student version.
You should post this question in nventor forum, you will get more feedback there. Click here to go to the forum.
And for you issue, it's a known issue. Windows 8.1. is still on preview stage and not officially supported yet.
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