Problems with the brush display.

[Katy32925089dr1h]

My softest brush with semi-transparent edges, which I've been using daily for 5 years, suddenly started displaying incorrectly. To be more specific, there's a pixelated halo around the brush. I have no idea what could be causing this. The only thing that might have triggered it was a Windows update before the last shutdown. I've tried everything – reinstalled Photoshop five times, reset settings to factory defaults, installed different Photoshop versions, checked all my graphics drivers, and even reinstalled Windows, but nothing has helped. If anyone has encountered this issue and knows how to solve it, please, help!

[Trevor.Dennis]

Goodness.  I was ready to say that soft brush halos are often a display issue when I saw the contents of your screen shot.  Even Crocodile Dundee would have to agree that 'THAT'S a halo!'

If everything looks normal to you, I'd be inclined to reset the Brush tool,  

[D Fosse]

Even with 16 bit data your display path is normally 8 bit, or even 6 bit + dithering for most office/gaming and laptop displays. 10 bit capable displays are rather expensive. So you will normally see some banding in shallow gradients, but this was a bit much.

This is almost certainly a GPU issue. Try to disable the GPU in preferences and check again.

It could also be a defective monitor profile. Bad profiles are often distributed by the manufacturers. In that case replace your current monitor profile with sRGB IEC61966-2.1 and try again. The proper way to deal with that is to use a calibrator to make a new profile.