Brush tool not available to draw on normal AI file
I can draw a line on my rough draft in a .ai file, but can't use the brush tool. It shows the O with a / "forbidden" symbol (not available).
Does it happen in every document you try?
What do you use when you try to draw a brush stroke, a mouse or a pen?
If a pen — what model is this, and what is the driver version for this?