It Seems like people are having trouble installing and activating leaked Windows 8.1 Pro Version because of the corrupted install.wim file. I have managed to install and also activate Windows 8.1 Pro RTM. Here is the procedure 1. Unmount using Dism as follows: Dism /Mount-Image /ImageFile:\Sources\install.wim /index:3 /MountDir:E:\Win8\Pro 2.Capture Image: Dism /Capture-Image /ImageFile:E:\RTM\install.wim /CaptureDir:E:\Win8\Pro /Name:"Win 8.1" 3. Create ISO: I have used w8boot-v1. Download it from here hxxps://mega.co.nz/#!Z5JR1RJC!LhzYrnUTRuSELBcz7DvgrGFvnjN1Z-gJqu69ELi-pJg a)Extract contents of w8boot-v1 to C:\w8boot b)Copy install.wim created in previous step using Dism and also boot.wim from RTM frankenbuild to C:\w8boot c)Run MakePatch.bat It will create "en_windows_8.1_rtm_x64.iso" in C:\W8boot d)Mount and install 4. Activation: Use Windows 8 Pro RTM key from your MSDN. Enjoy the activated Windows 8.1 Pro RTM. Screenshots: hxxps://mega.co.nz/#!ApByTT6D!QfZ25kiW-MFk7uqa_8CDg3OuYRBaMB1yQNl0sda5-ho hxxps://mega.co.nz/#!885W1LQC!a1uUEnEfuJQ9V9HVhNM2NmcQQukZAzWZcbkEBvkkRQY hxxps://mega.co.nz/#!NhpwFJZY!bi9PtT9pZRrFSCdWPZQPxW4D9NFWxJ69jzEImUM0XyE By the way leaked one is the Dell OEM Build.