I have recently build a PC, i installed Windows 10 on my 128GB SSD, but forgot to even set up my hard drive and i've only come across this now as i've run out of room on my SSD. The HDD shows up in Disk Management as Unknown and Not Initialized, although it does show the size of the disk. If i try to initialize it i get the error message "The request could not be performed because of an I/O device error." In event viewer, the description is "VDS fails to write boot code on a disk during clean operation. Error code: 800704D@02070008". I cannot for the life of me find any support online anywhere. I have used 3 different SATA cables and tried all SATA slots on my motherboard. Same error every time. I am using an ASUS Prime H370 Plus CSM Motherboard, and the HDD in question is a Seagate Barracuda 1TB ST1000DM010 3.5in Hard Drive. Any help would be appreciated, thanks.