Why is Mark Partition Active Greyed out in Disk Management?

Hi, Yesterday I used Disk Management on a couple of 16GB USB flash drives to create a New Simple Volume ran a Full Format on them both as FAT32 with a single partition. Both of them are set up as MBR drives so theres no issue there.
Then I decided I'd like to mark one of them as Active so I could set it up as a bootable installation flash drive.
On both of the flash drives when I right click on the drive the "Mark Partition as Active" option is greyed out.
Can anyone explain why?

That's interesting. I see the same greyed-out behavior on 1803 but I do see the option on 1709.



I am still able to mark the partition as active using diskpart. So this seems like a bug in 1803.

Yeah..I cant understand it. I never tried making a partition Active using Disk Management before but its interesting to hear you say it worked in 1709. Is it perfectly OK to use Diskpart to make the partition Active even if you've prepared the USB flash drive using Disk Management.... By that I mean created a New Simple Volume and formatted etc all in Disk Management. But then later on use Diskpart just for making the Active Partition only?
Im not 100% sure how to do that though

There's no problem with using diskpart to make it active. Disk Management even immediately recognizes it as active.

Code:

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online          465 GB  1024 KB        *
  Disk 1    Online           29 GB  1024 KB

DISKPART> select disk 1

Disk 1 is now the selected disk.

DISKPART> select part 1

Partition 1 is now the selected partition.

DISKPART> active

DiskPart marked the current partition as active.

DISKPART> exit

PolarNettles said:

There's no problem with using diskpart to make it active. Disk Management even immediately recognizes it as active.

Code:

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online          465 GB  1024 KB        *
  Disk 1    Online           29 GB  1024 KB

DISKPART> select disk 1

Disk 1 is now the selected disk.

DISKPART> select part 1

Partition 1 is now the selected partition.

DISKPART> active

DiskPart marked the current partition as active.

DISKPART> exit

Thanks for those instructions. If it is a bug Disk Management bug in 1803 ..hopefully Microsoft will sort it out

Actually, it looks like it's a BIOS vs. UEFI thing.

My 1709 install was in BIOS mode and allowed Disk Management to mark as active. I just reinstalled 1709 in UEFI mode and now the option is disabled.

cereberus said:

Nah - it is not a bug - just a restriction.



Your pc is set to UEFI, so disk management knows other drives do not need to be set to active as UEFI does not need partition to be set to active to boot from it.

Of course, if setting up usb for a legacy bios install on another pc, you do need to use diskpart.

Thanks Cerberus for clearing that up. Its always good to know why something happens in a certain way. Cheers mate

PolarNettles said:

Actually, it looks like it's a BIOS vs. UEFI thing.

My 1709 install was in BIOS mode and allowed Disk Management to mark as active. I just reinstalled 1709 in UEFI mode and now the option is disabled.

That's good to know..Thanks