HOW TO FIX PHOTOSHOP PEN PRESSURE NOT WORKING :
IF your Photoshop suddenly stopped recognizing pen pressure from your tablet please try these methods bellow -
1st Method :
1. uninstalling the drivers
2. checking wintab files were gone from system32 and sysWOW64
3. restarting
4. reinstalling drivers
5. checking new wintab files are present
6. restarting
Reset the Photoshop preferences.
Start PS and immediately hold down Ctrl/alt/shift keys. If fast enough you will get a reset window.
and tick and enable pen pressure from the upper menu bar.
3rd Method :
create a PSUserConfig.txt file, drop it in your C:\Users*Username*\AppData\Roaming\Adobe\Adobe Photoshop CC 2018\Adobe Photoshop CC 2018 Settings\
put this inside the text file, and it should work on reboot. I just did the same for mine when upgrading today.
Use WinTab
UseSystemStylus 0
UseSystemStylus 0