On my PC in Disk Management when right clicking on the USB flash drive the mark partition as active option is greyed out so its not selectable. So I would have to go back into Diskpart to make the flash drive Active. To do that would these be the correct commands?
diskpart
list disk
select disk # (enter flash drive number)
list partition
select partition 1 (this would be the only partition on the drive)
active
exit
It is possible for a USB to neither have an MBR or GPT table but still be supplied pre-formatted by the manufacturer. In such cases Disk Management cannot mark the partition as Active as there is no MBR table, so the option is greyed out. Once Diskpart has been used to clean the usb and create a primary partition it will have an MBR table and can be marked Active by disk Management.
See this post for an example of a usb without a partition table.
Cumulative Update KB4048955 Windows 10 v1709 Build 16299.64Bree said:
On my PC after a flash drive has been cleaned and the convert mbr command has also been used...when I then go into disk management the mark partition as active is greyed out so its not selectable. Ive checked this out before so I know its correct. I asked about that before on another thread and other forum members said it was the same on their PC too and it was because it was a UEFI system so the option deliberately gets greyed out. I was informed that it is designed to be that way on Windows 10. Im aware that on a UEFI system the Active command isn't necessary but it would also make the bootable flash drive also bootable on Legacy boot if ever needed. I know then that making it Active would create the flash drive in exactly the same way as the Media Creation Tool does when it automatically creates the USB media for you.
So to make it Active Id have to go back into Diskpart. So would these be the correct commands to type in?
diskpart
list disk
select disk # (enter flash drive number)
list partition
select partition 1 (this would be the only partition on the drive)
active
exit
Last edited by sportsfan148; 15 May 2019 at 13:13.
Odd, I have no such problem after using Diskpart 'Clean, Convert MBR, Create partition' on this Lexar 8GB USB....
What version of W10 do you have? Mine is 1809.
Yes, those are the correct commands.So to make it Active Id have to go back into Diskpart. So would these be the correct commands to type in?
diskpart
list disk
select disk # (enter flash drive number)
list partition
select partition 1 (this would be the only partition on the drive)
active
exit
Thanks for confirming that Ive got the Diskpart commands entered correctly.
Im on Windows 10 version 1809 too. I think when I had the original conversation on here way back and other people said mark partition as active was greyed out on their UEFI systems too that I might have been on 1703 or 1709 maybe. It was a Sandisk 16gb Ultra 3.0 but I wouldn't have thought that should have made any difference as others were seeing the same as me in Disk Management
My first screenshot was 1809 on a Legacy system. I have confirmed that on a UEFI install of W10 1809 the Disk Management option to 'Set Active' is greyed out for ALL disks, removable or otherwise. Whether that's by design or mistake, your guess is as good as mine. Here's the SAME usb on a UEFI system....
So on a UEFI system Diskpart is your only option.
Yeah..its exactly the same on my system. Like I said it was the same over a year ago too. So it looks like its either by design as I was told or its something that's been overlooked somehow on Windows 10My first screenshot was 1809 on a Legacy system. I have confirmed that on a UEFI install of W10 1809 the Disk Management option to 'Set Active' is greyed out for ALL disks, removable or otherwise. Whether that's by design or mistake, your guess is as good as mine. Here's the SAME usb on a UEFI system....
So on a UEFI system Diskpart is your only option.
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