problem with diskpart

hi there,

In order to reclaim unallocated space on a USB stick , I was recommended to use DISKPART
But something went wrong.

I used the following commands:

1) DISKPART
2) LIST DISK
3) SELECT DISK 3 ( I used Disk Manager to find that out)
4) CLEAN
5) CREATE PARTITION PRIMARY (here something went wrong. Error message: disk not valid)

When I checked back with Disk Manager I could no longer access Disk 3. It has disappeared completely.

Can somebody help me to sort this out? The capacity of the USB drive (stick) is 64 GB and half of it was unallocated, so it was a real bother, and I wanted to fix it. Unfortunately I must have done something wrong, and now the whole stick is unaccessable.

Have you tried removing the USB flash drive. Restart the computer completely by clicking on restart from the power button icon on the start menu. Then re-insert the USB flash drive after the computer reboots - preferably in a different USB port than it was in the first time. See if it reappears then. If it does not, I would suggest opening device manager and see if there are any "unknown devices" or hardware with exclamation points indicating a problem.

I also suggest you use MiniTool Partition Wizard free to partition the 64GB USB flash drive exactly the way you want. Windows built-in disk management tends to only want to use 32GB of flash drives.
Best Free Partition Manager for Windows | MiniTool Partition Free

Thanx alot it really worked, but another error message popped up when trying to format the 64 GB USB drive with the command :

format fs=fat32 quick .
A virtual disk service error which said it could not handle that many gigabytes. I've formated this drive with Windows 10 before, so I know it is possible. Are the recent windows creator updates at fault?

That's the limitation imposed by Windows on the FAT32 file system on a USB flash drive - 32GB. If you are going to format the flash drive as FAT32 using diskpart - the partition you create must be no larger than 32GB. Microsoft now allows more than one partition to be on a flash drive with Fall Creator's Update, though.

I don't have a >32GB flash drive at the moment. That's why I suggested trying MiniTool Partition Wizard, though.