Apologies if this has been gone through before but the 5d error seems to be a pretty common problem that I may have found a new working solution to.
I was having a major issue installing Windows 8 in a VirtualBox VM running on a Windows 7 Ultimate host OS.The install process would start, then promptly stop with the dreaded 5d error message indicating that it thought that NX/XD/DEP either isn't available or isn't turned on.
I checked and re-checked all setting and it all looked good, the CPU supports NX/XD/DEP and it was turned on in the BIOS and turned on in the VirtualBox VM System Settings but it still wouldn't install. I checked the CPU capabilities with CoreInfo and SecurAble and they both confirmed that all the required CPU features for Windows 8 were present and correct and that NX/XD/DEP
was enabled and available, but Windows 8 still refused to install.
I was doing some digging online and came across a post that mentioned the DEP settings in System Properties, Advanced, Performance, Settings, Data Execution Prevention. This setting has been in Windows since XP I think and the default on my existing Windows 7 host was set to 'Turn on DEP for essential Windows programs and services only'.
I changed this to the 'Turn on DEP for all programs and services except those I specify', rebooted the machine as requested and then when I try to install Windows 8 in the VirtualBox VM, voila, it works.
I've been battling this problem for weeks now and finally have a working Windows 8 VM so I can get on with my testing having tried just about all the other suggestions to the 5d error I could find online without success.
I thought this would be worth while sharing.