In the Command Prompt window, enter diskpart, and then press Enter. (To do this, right-click Command Prompt and select Run as administrator.). If you have formatted your USB flash drive with COMPRESS, you have to move to it in Windows explorer, right-click bootmgr and bootmgr.efi, select Other and uncheck Compress contents to save disk space. (The USB drive should be at least 16 GB.) Open a Command Prompt window as an administrator. In Windows 8 and 8.1, ISO files are mounted as virtual CD / DVD drives and the files can be copied using Windows explorer. In Windows Vista and Windows 7, you’ll have to use third-party utilities, such as WinRar, 7Zip, Far Manager, etc. You downloaded a Windows 7, 8, and 10 installation image in ISO format officially and legally direct from Microsoft. Now you have to extract files from ISO images of Windows 8.1 distribution to your USB flash drive.
#BOOT USB ISO WINDOWS 8 WINDOWS 10#
If you are using a newer Windows 10 ISO (after version 201809), then UUByte ISO Editor is the best app for creating a bootable USB on Mac. If you have a USB flash drive with the size of 8 GB or more, you’d better not specify the COMPRESS and UNIT=512 parameters, because it takes more time to copy your files to the USB flash drive when you are using them. I managed to create several bootable Windows 10 USBs on Mac (Mojave, Catalina and Big Sur) in recent years. However, there are a lot of small files in the distribution of Win 8.1, so we’ll make the data placement denser. UNIT=512 sets the cluster size to 512 bytes.
#BOOT USB ISO WINDOWS 8 HOW TO#
In the second case, in the command FORMAT FS=NTFS QUICK COMPRESS UNIT=512 it is the difference from other manuals on how to create bootable USB flash drives.ĬOMPRESS means that compression will be applied to the NTFS files on the USB drive. Pay attention to the text highlighted in red. In the line select disk 1 it is a number of the USB flash drive. With it, you can enter a WinPE environment and use this software to repair Windows boot failure problems by rebuilding MBR, checking and fixing possible bad sectors. DiskPart successfully formatted the volume.ĭiskPart successfully assigned the drive letter or mount point. Note: Besides burning ISO image files to USB as a portable Windows device, AOMEI Partition Assistant Professional can also create a bootable USB drive.