I had Auslogics Defrag Pro installed on my Windows 7 computer and was able to do Simple defrag, Free space optimization, and Optimize by Prefetch Layout without any issues. I installed Auslogics DefragPro on my new Windows 8 and tried to run Optimize by Prefetch Layout, but got a message that "Prefetch needs to be enable to perform optimization". I received an answer from Auslogics Support telling me to ============================= "enable Prefetch by going to KEY: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters Name: EnablePrefetcher Type: REG_DWORD Value: 1 After that we advice you to wait around 5 days." ================================== I've changed the registry key but still unable to run Optimization by Prefetch Layout. I would be very grateful for any help.