Thank you for your response.
Maybe there is something that I need to check to find out why it's not working on my end.
As I stated I have reset Maya to default preferences.
I am not doing anything complicated.
I imported the HumanBody from the Content browser.
Created a few joints, couple up the spine and then a shoulder, elbow and wrist joint.
I then used the Bind Skin - default settings
I rotated the arm shoulder joint
I then open up the Tool Settings for Paint Skin Weights Tool
Select the geometry,
In the Paint Skin Weights tool setting window, I select the Joint.
The icon is the standard round brush icon, but when I hold down B and MMB the mouse Icon changes to the double arrows, however, when I drag left and right Nothing happens.
If I RMB click and select Paint Selected Mode from the popup, I can change the size of the brush using B + MMB. It is very sluggish, but at least it works.
My System:
Intel(R) Core(TM) i7-9700K CPU @ 3.60GHz 3.60 GHz
32.0 GB Ram
NVIDIA GeForce RTX 2080/PCIe/SSE2
Maybe there is some video out there using the newest version of Maya that goes over how to do this?
Maybe I'm doing something incorrectly.