ExFat For USB Stick Problem

[Robert4]

Hi,

Nothing is ever "simple," I guess.
Running High sierra.

I have a brand new SanDisk USB Stick.
USB 3.0 32GB

Thought before using it, I would format it to ExFat.

I used the Mac Disk Utility, and all seemed to go well.

But, when I now insert it, it says: "The Disk you inserted was not readable by this computer"

It gives the options of "Initialize," and "ignore".
The icon for the stick is greyed out in the Disk Utility that comes up, if I try the Ignore button

Neither seems to do "anything".

Any idea what I might have done wrong, or how to correct ?

Thanks,
Bob