Is there anything you can tell us that might tie it down? Are you using a tablet, and if so, which one?
Have you tried opening Photoshop with the Shift key held down to force plugins and extensions not to load? I don't know if the issue happen often enough for that test to be useful.
Are these particular image types? Mode, bit depth?
Any particular brush presets? Do you always look at the Options bar to see if anything is going on up there (blend modes etc.)?
You mention a reinstall, but that does not necessarily give you a clean start with new settings, so resetting Preferences might be worth a try (sorry — we hate suggesting that unless all else fails as it is a PITA)
When you reinstalled, did you run the cleaner tool?
using a Wacom intuos 4, latest driver
I haven't reinstalled any 3rd party plugins since I reinstalled PS.
literally happens with any file type; and now I've had to restart PS because when I open a file, 6/10 times a healing brush, patch tool, clone stamp, or brush will result in absolutely nothing, even though the history palette is logging each stroke. nothing is selected, no blend modes, nothing.
this is on a fresh install of macOS as well. so there are no previous versions of anything on the machine. this is annoying and frustrating as it is increasing my work time unnecessarily.
I'm sorry, but I am out of my depth with Mac issues of this nature. I have changed the thread subject line to indicate that you are using a Mac, and this post will bump you to the top of th page again, so apart from that I can only wish you good luck.
I do remember seeing references to OSX versions and compatibility with different Photoshop versions, but 10.12.6 shouldn't be a problem
There's a long thread here that might have relevant content towards the end
I think Jeff Tranberry has a page as well. Hmm I'm not finding anything current
I'm guessing that your hardware would not support later versions of OSX seeing as this is a new clean install? Like I said... I am a Windows user.