Windows 8 Preview – How to Unblock Downloaded Files

While it is downloading the files will be stored in %AppData%\Local\Microsoft\Websetup

And after the download before the install you can find them in C:\WindowsESD

I had this problem and had to do two things to get my USB flash drive installation to work:

1. Boot into Windows 7. Instead of running autorun or \setup.exe, run \sources\setup.exe. This gets around the "Something happened" issue you are seeing.

2. That got me further, but I got a dreaded meaningless error: "an error prevented a required compliance check from completing". All I did was go to the Windows 7 Disk Management (Right-click Computer, click Manage, then find Disk Management), and make sure my existing windows partition (that I am upgrading) is marked active. I right click it and click "Mark Partition as Active". (It may also need to be a Primary partition and marked as Boot, but that was already the case for me.)

(My setup: my USB stick was created by Apple's Bootcamp assistant using x64 Windows Consumer Preview, for my triple-boot Macbook Air that boots using EFI loader and then Grub for Win/Linux.)

Also, I don't know why I can't comment on the other answer, regarding corruption, but Microsoft provides the SHA 1 hases for the iso images right on the download page. (I used the convenient Windows Explorer properties window extension called Summer Properties to verify the hash.) (Oh, I just discovered I can't comment because I am riffraff who just walked in off the street: 50 reputation needed.)