This might be the reason why the Debian Stretch Alpha 7/i386 installation does not complete the Partition Formatting step. It gets stuck at about 30%. I am using Windows 2012 R2 Hyper-V platform and tried both VHD and VHDX virtual drives. This is not a problem with the current Debian 8.5.0 Jessie/i386 installation. I am a novice, so I don't know how to troubleshoot or work around this issue.