The red brush preview requires the Use Graphics Processor checkbox to be enabled. Go to Preferences > Performance... and make sure it is checked. If it is checked, there may be a problem with your preferences. Restore your preferences using this manual method: https://helpx.adobe.com/photoshop/using/preferences.html#Manually Does it work correctly? If that doesn't solve it, you can quit Photoshop and put the Settings folder back. If it does solve the problem, I would like to get the folder of settings to try and figure out what is bad with them.
Senior Product Manager - Customer Advocacy - Digital Imaging