P: (macOS Sonoma) Photoshop 2023/2024 Save for Web shows incomplete preview

No, stable like I mentioned. 14.0.

Are you using Sonoma 14.1 (Beta) on your Mac Mini M2 Pro?

Datapoint possibly worth noting: I have the Save for Web bug on macOS Sonoma on my M1 MacBook Air, but not on my M2 Pro Mac Mini. Both running the latest stable OS update + Photoshop 2024. 

On the M1 with the issue, I also noticed rectangular selection dancing ants were not showing up at one point.

I agree, while noting that the whole point of public and private betas is so software writers can find these issues and fix them. 

Given that this seems to only affect Save For Web, this is apparently Sonoma tripping over the very old SFW code.

So now we can only hope that "Legacy" doesn't mean completely abandoned. As @Stephen Marsh implied above, there's a very good reason people still use Save For Web: Export is unfinished. Finish the job, and we can say goodbye to SFW. Until then, I think they have a responsibility to keep it fully functional.

Yes, but it won't fix the problem, it'll just make Photoshop faster. The only "fix" is using the export dialogue which isn't as featured, and waiting for Adobe to have a fix or to pass the buck to Apple for a fix.

When I click "Save for Web" it only show a portion of my canvas and the color table shows up blank. I reinstalled it and even updated Photoshop and I am still have this issue. 

still having the same issues after doing this.. should i check "Use Graphics Processor" again?

I'm having the same issues with save for web in Ps ever since i upgraded to sonoma 14.0 but much worse! I can't see the previews and it doesn't allow me to change the settings per slice.

Regarding the elephant in the room... I think that it is important for Adobe to know and understand, WHY users "persist" in using the outdated code in Save for Web, when the new Export As feature exists.  :]