Hi
How to completely format a bootable USB flash drive because I found there's a partition on the flash drive named "UEFI_NTFS" (EFI > Boot & Rufus folders with .efi files inside) that cannot be formatted.
My other bootable USB with MBR partition can be fully formatted.
I still keep the Win10 iso file & Rufus if needed.
Thanks
UEFI and MBR are two different formatting systems,
The old MBR system used to hide it's required files on a single partition, where they were liable to be deleted by normal operation while using the disk.
UEFI, on the other hand takes the safer and more secure route of placing it's required files in one or more small partitions at the start or end of the physical disk space.
If you ever require to re-use an UEFI formatted disk for MBR you need to delete the hidden UEFI partition(s) using partition manager software before you can use them .
In theory, a Full format from within Windows (as opposed to the default Quick format option), should remove the UEFI partitions and reformat as MBR, but I would always recommend using the Partition manager method to be sure
If full format does not work then use Diskpart command:
Use the USB Disk number listed to replace X letter.Code:Diskpart list disk select disk X Clean all
Diskpart's CLEAN ALL command will remove all partitioning and write zeros to all sectors. If security isn't your concern then just use CLEAN on its own. This will remove all partitions, but will not overwrite all sectors. Using CLEAN ALL on an SSD or USB memory stick can wear it out and reduce its life, unnecessary writes should be avoided if possible.
"Completely" formatting will not remove partitions. Use Windows Control Panel > Administrative Tools > Computer Management > Disk Management (or 3rd party software) to delete partitions, and then recreate partition.
Posts #3 and #4 above have the answer:
Code:diskpart list disk select disk # <- replace # with the actual number of the flash drive clean <- this will remove all partitions on the drive selected above - and for flash drives it also reverts it back to MBR exit exit
Thanks all
I've formatted the USB flash disk using diskpart command, now I can reuse it
Much appreciated ...
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