Install unable to write files Parallels 7 on Mac host - downloaded Windows 8 Developer Preview. iso file used in Parallels as boot source. Tried Windows 7 and Other Windows as OS type - 64bit 1GB RAM 2 CPUs - gets to Expanding Windows Files around 91% and then says - Windows cannot install required files. The file amy be corrupt or missing. Make sure all files required for installation are available, and restart the installation. Error code: 0x80070570 tried 32 bit and had the same trouble.