Have you ever had the creative juices flowing, your favorite music blaring, and selected your Photoshop brush, only to find that your cursor disappears and you can't see the brush outline? Photoshoppers everywhere have endured this little annoyance for years. It's really quite simple to avoid, but until you know why, it can be quite a thorn in your side.
So you have your brush selected and all you see is a cursor like the one in the screenshot above? All you need to do is deactivate the Caps Lock on your keyboard, and you should see your brush! What was happening is with Caps Lock on, you are enabling “Precise Cursors,” a feature that is also accessible from Preferences > Cursors.