I'm getting this error too! Using Windows 7 Ultimate x64 (OEM System Builder Pack) p/n X15-46015-01. This was an install off the CD, not using an unattend, and attempting to run Sysprep /OOBE /Shutdown. Nothing special here. This is my first time installing Ultimate, have done 3 Home Premium x64 without a problem. The Panther logs are showing two sets of infos: an hr=0x80070020 (ERROR_SHARING_VIOLATION) gle=0x20 (KERNEL_APC_PENDING_DURING-EXIT) and dwret= -2147024864 gle=0x20 So I am not doing anything with images or generalizing. All that is done is install the OS, then install the Windows 7 drivers (for Intel DG45ID) and no additional software. However, I went into services and STOPPED the Windows Media Player Network Sharing Service, and then set its start-up state to Manual. It was able to sysprep the computer without an error.