1. If I disable Start is Back for current account, the wallpaper will back to normal. so it must be something wrong with my settings or SiB. 2. If i DISABLE the shuffle of change wallpaper. everytime when I boot into windows, the wallpaper will ALWAYS change to the first image (After the "Pure color" and I click "next background") 3. I'm still sure all the images are okay. Because all of them can be correctly previews. Also I download them from Microsoft's server manually. So if any of them were wrong, I will not be the first one meet this problem. I'll try more staff like change the path of wallpaper of use different images after I got home. But give some system information here first: System: Windows 8 Pro (S-Chinese edition, UEFI Boot, Secure boot ON, TPM / BitLocker ON, Fingerprint Login) Login with Microsoft Account. Antivirus: Norton Internet Security 2013 SiB version: The Newest one (in 2013-03-22) Wallpaper source: http://windows.microsoft.com/en-gb/windows/themes -> RSS dynamic themes -> Terra Dynamic Anything more you want, just let me know.