Camera Raw Brush not working [Mac]

[JulieK2]

Hello, can anyone help please, the brush for selective adjustments in Camera Raw filter suddenly stopped working, it was fine before. It lets me chose the location for the adjustments, but then when i move the cursors to change the saturation for that spot, for example, it does not change anything, the colour stays the same

[Trevor.Dennis]

It looks like you are using a Mac from the tabs you have applied.  Can you tell us what version?  Just in case it is relevant.  

Can you also clarify whether you are talking about opening a RAW file in Camera Raw, or using the Camera RAW filter on an already open image?

Thanks

[JulieK2]

Thank you Trevor, 

its an IMac 2012

photoshop 2020

im talking about camera raw filter on an already opened image. All of the adjustments are working fine in the camera raw filter except for the brush, which I occasionally use for selective adjustments. It's been working fine till a few days ago.