Recover USB stick from Memtest86?

This is stupid. I created a new bootable memtest86 onto a small 4GB USB stick. All OK.
Now it says that it is just a 26MB drive! So I went to diskpart and did a CLEAN. Great, and it shows 4GB unallocated.

NOTHING I try, even a Create Partition Primary will then let me format this stick to make it usable again.

Does anyone know how to do this? I have searched and all of everyone's suggestions do not work. What am I missing?
OH, I am using 64 bit Win 10 Pro.

I did it myself...

DISKPART> list disk
DISKPART> select disk (id)
DISKPART> online disk (if the disk is not online)
DISKPART> attributes disk clear readonly
DISKPART> clean
DISKPART> convert mbr (or gpt)
DISKPART> create partition primary
DISKPART> select part 1
DISKPART> active (if this is the boot partition)
DISKPART> format fs=fat32

OMG , sorry to get that problem. i just want to know you just need to use the USB stick to make a a new bootable memtest86 , right ?

Molyy said:

OMG , sorry to get that problem. i just want to know you just need to use the USB stick to make a a new bootable memtest86 , right ?

No, I just wanted to bring back the stick to 4GB. After creating the Memtest86 USB bootable stick, you can not erase it and get the stick back to the original capacity! NOTHING I tried, except the above, fixed it.

Caledon Ken said:

These instructions come from this link. http://superuser.com/questions/54760...mtest-from-usb

1. Insert USB Disk.
2. Launch the imageUSB program that you used to create the MemTest86 USB and select the appropriate USB Disk. (Be careful and select the correct drive!).
3. Choose the Zero USB Disk option & Run.
4. Drive MBR (Master Boot Record) is now Zeroed. You will need to reinsert the drive for Windows to recognize it and prompt for formatting before you can use it again. A normal format will now recover the full capacity of the USB drive.

Been there and tried that first. They even said it may not work and in my case it did not. Anyway, the Doskpart did work but you have to be very careful!