After 3 days of fruitless searching and multiple attempts to install 8.1 I finally found the answer. My hardware does not have the required LAHF/SAHF support nor does it support Prefe6tchW. Why this matters now withe the 8.1 update when it does not matter with 8 is beyond me.
See here: Can't install or upgrade to 8.1 Preview - Microsoft Community...
↧