Two days ago I bought a USB stick, formated it as Fat 32, created a Win PE and copied it on th stick. Booting fom the USB key wasn't successfull. After making the partition of the stick active, booting was OK. So I supposed the partition has to be active, but may be I'm wrong and my first booting attempt failed for an other reason.
It's the official MSFT supported way to create an UEFI and Legacy BIOS bootable USB install-media. It has been discussed manymanymany times, i've used it hundreds of times and just formatting the USB drive FAT32 in explorer works, Tito added one bit that it maybe not works on older particular systems but that problem i haven't encountered. There are many replies it also works for many others. I'm not talking about any (homebrew) winpe disk, i'm talking about windows installations (vista, 7, 8.x and 10).
Sorry, I don't want to engage in polemic, but I don't agree with you. I just took an USB stick I used before to install Windows 10 (not a homebrew winpe disk), marked the partition inactive and tried to boot on this USB stick : failure. Following this test, I marked the partition active : boot OK.
Don't mark or unmark anything, just format FAT32 using explorer and extract the iso to the root of the usb and it works, i've installed only the past 3 days windows 30+ times using the official MSFT method. On many different usb thumbdrives.
@rpo This always works for me, clean usb stick with HDDLLF.4.40, then use diskpart cmds. Code: diskpart list disk select disk x clean create partition primary select partition 1 format fs=ntfs quick active Then Extract Windows ISO to usb. Then cd to the boot folder on usb, if usb is on F: use these cmds. Code: F: cd boot bootsect /nt60 F:
Why would you erase the memory twice with llf and then with diskpart clean, this is beyond unneeded, just format as fat32 and extract the .iso, works all the time.
Absolutly. Let's be clear : You just have to format your USB stick as ntfs or fat32 (if you have to boot on an UEFI sytem) and extract the .iso to it, BUT the partition on the stick has to be marked as active; if you get an new stick it is possible that the partition is not marked as active : you can format it, copy files on it but it is not bootable. Once the partition is marked as active you'r done and you don't have to worry about it for future operations. The code provided by Ace2 includes the Diskpart active statement and the MS MCT tool seamlessly markes the partition active while copying the iso image on the stick. I believe we can now conclude the debate.
@Enthousiast, This is like a dialogue of the deaf. This is what I mean : if for some reason the partition of your USB stick is not marked as active, you will not be able to boot from this USB stick. That's all.
If my memory serves correctly the active mark is not required for UEFI boot but for MBR one . At least it was needed to boot the grub loader from my Win10PESE in MBR.
Without having done any tests, I would guess that the difference between the two boot methods reduces to whether or not the USB stick actually has an MBR: If it has been "partitioned" MBR-less, i.e. the partition itself starts at sector 1 without a prepended MBR, the OS-specific partition boot record (PBR) will be invoked directly at startup and take control of the boot process. In this case, there is no need to set anything "active": There is no place to set this flag anyway, because no MBR means no partition table. If the USB media actually has an MBR at sector 1, which will be invoked at boot, the MBR code will search through the partition table and only relay boot control to the PBR of a partition with the active flag set. Anyway, just a guess. To be sure, you'd have to look at the first sector of your USB sticks in a disk/hex editor.