1. Open “System Preferences”, then “Security & Privacy”.

2. On the “Accessibility” setting, make sure “PenTabletDriver” and “PenTabletSetting” are both enabled.

3. Open the tablet setting and make sure you can test pen pressure with it. 

4. If the pen pressure works, open PS. 

5. If you get Accessibility Access (Events) error message, click “Open System Preferences” button. 

6. On the “Security & Privacy” – “Accessibility” tab, click “Unlock” first, then “enable” Adobe Photoshop, and then close it. 

7. Close PS on the Dock and open it again. Pen pressure will now work in Photoshop.