Someone volunteers to score the game. That someone owns a Mac. Two hours of searching later they have learned that nearly every recommendation points squarely at Windows, the forum threads discussing it are a decade old, and one of them is mildly hostile.
It is a genuine gap. Worth understanding why it exists before you go hunting for a workaround.
Why the Windows problem is real
Duplicate scoring software for clubs and tournaments has a long lineage. ACBLscore, still the backbone of sanctioned play across North America, began life as a DOS program and grew into Windows from there. The hardware that assembled itself around it, the wireless scoring units and their control software, followed the same path for the same reasons. None of this was a decision anyone made against Mac owners. It is simply what happens when a piece of software is written in 1990 and never gets a compelling reason to move house.
So the honest answer to "what runs natively on macOS" is: less than you were hoping. Directors who use Macs tend to run Windows on them, through virtualization or Boot Camp on older Intel hardware, or they keep a wheezing Windows laptop in a cupboard purely for game night. Not elegant. Works fine.
Most people typing this search, though, are not sanctioned club directors.
Sort the software by what it does, not what it runs on
The word "scoring" covers two completely different jobs, and conflating them is why this search feels murky.
The first job is arithmetic. Four hearts doubled, vulnerable, making five: what is that worth? A lookup, nothing more. The only genuinely fiddly part is the conversion from raw scores into matchpoints, and even that is arithmetic once you have seen it done twice. Any phone handles it. Any of the small apps handle it. The operating system is irrelevant because you are not installing anything serious.
The second job is running a field. Handling a movement. Tracking which pair sat where on which board. Collecting a result from every table for every board, matchpointing each board across the entire field, then producing a ranking that survives someone squinting at it afterwards. That is a database problem wearing a bridge costume, and it is exactly where the Windows-heavy programs live.
Decide which of the two you actually need. The answer changes everything, including whether the Mac question matters at all.
Three routes that actually work
The browser. Anything web-based is platform-agnostic by construction. macOS, an iPad, a borrowed Chromebook, none of it matters, and there is nothing to install or update at eleven in the morning on game day. This is where most of the newer scoring tools have landed, and the reason is not mysterious. Bridge scoring is not computationally demanding. It is bookkeeping, and bookkeeping is perfectly happy in a browser.
Windows in a box. Directing a sanctioned club game and need masterpoint files the league will accept? You will end up running the official program one way or another. Parallels, or a secondhand Windows laptop for the price of a nice dinner. Do not fight this one. The requirement is administrative rather than technical, and administrative requirements do not care how you feel about them.
A spreadsheet. Underrated, genuinely. Numbers or Excel will matchpoint a small game perfectly well, provided someone builds the sheet once and tests it against a session that was already scored by hand. The catch is that the sheet is only as reliable as its author, and a formula error on board nine stays invisible until somebody recalculates. Two or three tables, defensible. Past that, the odds start collecting. We went through the paper versus spreadsheet versus app tradeoff in more detail elsewhere.
The question underneath the question
Something else usually sits beneath this search. Plenty of the people hunting for duplicate scoring software are not running a club at all. They have four friends, a kitchen table, and a nagging sense that the evening ought to add up to more than it does. They came across the phrase "duplicate scoring" and correctly guessed that duplicate is where the meaning comes from.
For them the software question is a red herring, because scoring was never the missing piece. One table produces one result per board. Matchpoint that against nothing and you get nothing back. Speed of arithmetic was not the bottleneck, which is precisely the trap most bridge scoring apps walk straight into.
What that group needs is a field to be measured against. That is the design idea behind Bridge@Home: the four of you play pre-dealt hands at your own table, and every board gets scored against everyone else who held those same cards. It runs in a browser, so the Mac question quietly evaporates. More to the point, "we made four spades" turns into "we beat seventy percent of the field on that board", which is a completely different sentence to say out loud.
You still need four players. No software has ever solved that.
The takeaway
Sanctioned club game with masterpoints on the line: get Windows running somehow and use the official program. Nobody has found a way around it, and the workarounds cost less than a set of boards.
A regular multi-table game with no masterpoints attached: choose something browser-based and stop thinking about it. You will spend longer choosing than the software will ever cost you, in money or in trouble.
One table in the living room: you do not have a software problem. You have a comparison problem, and honestly, that is the more interesting one to solve.