Need to reformat USB Thumb -- any recommended third party software?

Usually the manufacturer has a utility on their site to fix/reset thumbdrives.

If Disk Management won't allow you to format it, then it is probably a bad drive and needs to be replaced. With the Flash drive in, Press the Win key+S in the Search box type CMD, right click the CMD results and Run As Administrator.
In the Elevated Command Prompt type Diskpart then type the following Bold commands pressing Enter after each one.
i) diskpart
(ie) DISKPART >
ii) list disk
(ie) DISKPART > list disk
It now lists disk by number you have to select the disk next with
iii) select disk <disk number>(ie) DISKPART> Select Disk (disk number) = as listed in previous command. The selected disk now has an Asterisk next to it
.iv) clean
(this erases all data on the Disk, so be sure you choose the correct one) (ie) DISKPART> clean

Now you can go back to Disk Management and the drive should be Unallocated Space, You then can Right click it and choose to make a new Simple Volume. and Format it.
If this fails, the Flash drive is most likely bad and needs to be replaced.

The Pool Man said:

I have a thumb drive which Windows Disk Management Command line tricks won't fix. Does anyone recommend a third party software for this?

by disk management you mean Diskpart?

Here on Easeus page are complete tutorial for Diskpart, and at the bottom a tool to do it.

Otherwise, I would recommend Minitool partition wizard.

Check, if it is write protected.

Open registry editor and find

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies

Find "WriteProtect" key and set it to 0 - DWORD (32-bit)

The Pool Man said:

Andre for THE WIN

Glad it worked