# Method3: Recover Unallocated USB Drive Space using third-party Partition Software. Install Windows 10 on New Hard Drive Without USB. Follow the mentioned steps to open the command prompt at the installation screen. 0MB indidicates that the BIOS thinks your drive has absolutely no free space and the drive basically does not exist. However, due to Boot Camp’s tricky partitioning of a hard drive, legacy mode will not allow Windows installation to that partition (the infamous message “Windows cannot be installed. Windows cannot be installed on drive 0 unallocated space Choose C Drive from the drop-down menu ‘Merge selected volume to’.
