P: Hang while using Shawdows/Highlights tool with the Histogram panel showing (macOS)

Having the same issue here. New 16" Mbp fully specked out running Catalina 10.15.3. Please solve this Adobe.

What I did was uninstall and reinstall without the preferences. That worked for me.

Resetting prefs has no effect at all

Thanks - tried that.  Didn't work.  Also tried typing into the box but no use either.

Mac 10.14.16  No Bit Defender!

You need to trash your preferences and it will fix this.  A PITA for sure, but it solves the problem, and it is not a bad idea to have a look at those preferences from time to time.

Another suggestion I saw elsewhere instructs to enter values directly in the dialog box rather than using the sliders. It worked for me, though it's far from ideal and let us hope that Adobe fixes the bug in the next update. Bad Adobe. Bad.

Imac 2017 27 inch MacOS High Sierra 10.13.6 > PS 21.1 Shadow/Highlighlight filter freezes PS everytime. Have to Force Quit & restart the App - cannot use S/H filter at all on .jpg or .psd files - please resolve - never had this problem before - been a mac PS user since late 1997

Reset your prefs. Hold Cmd + Opt + Shift while opening photoshop.

I've reverted back to v21 got an offline installer from Adobe. Just have to wait until there release a new patch

Since my last post I have also found that using the Refine Edge Brush when doing Select and Mask doesn't work properly. Either nothing happens or the mask edge gets corrupted and "messy". This is happening on both an iMac and also on a latest fully loaded iteration of the Mac Mini. Both are running Mac OS 10.14.6 (Mojave). Even calling up the old Select Mask via the Alt Key and then choosing Select and Mask doesn't fully resolve the situation.

Is anyone else experiencing similar and if so have you found a workround?

I have also posted this additional problem under a separate heading and on the Photoshop Support Community board but thought it worth posting here as well.

This 21.1.0 release seems to be full of bugs and needs resolution asap.