How’s the 32-bit cleansing going? Would another tool help?

It’s amazing to think that around six months from now, many of us should be running the release version of macOS 10.15, and in only two months time brave beta-testers will be starting to discover what it has in store – including its inability to run 32-bit code.

I recently purchased a ‘home use’ licence for a heavyweight app, and was more than surprised when I first ran it: Mojave complained that its current version is still 32-bit. I wanted to check this further, to establish exactly which of it is still 32-bit, but found the macOS Legacy Software tool less than informative, and my own 32-bitCheck not quite what I wanted.

What I wanted to do was to drag and drop the app in question onto a tool which would tell me:

  • Exactly which architecture(s) the app itself supports.
  • Which, if any, of its executable code is still only 32-bit.

I tried a couple of other tools I happened to have to hand, but none did what I wanted. It was a wet and windy afternoon, so rather than going out walking, I put together a little tool to do just this: ArchiChect. As I have just given it a suitably garish custom icon and got it notarized, I thought that someone else might find it useful too.


It has a very simple interface which tells you exactly which of the four current architectures the app, code bundle, or command tool supports. Suspecting that we might see additional architectures appearing in the not too distant future, I have added a box to show any other result too. Below that is a straightforward list of all the components within the app or bundle which are 32-bit only.

You can save this to a text file for posterity too.

There’s one slight limitation in this first beta-release: don’t try opening an app or code bundle using the Open command in the File menu, as that currently thinks it’s a plain folder rather than a bundle. The Open Recent command works fine, though, and this is primarily intended for use with drag and drop. If you throw something particularly large and complex, like Xcode, at it, be prepared for the window to take a while to appear, after a show of the spinning beachball – there’s an awful lot of code to be checked there, and it does take time to do it thoroughly. If you want to run heavyweight checks on folders, 32-bitCheck is the tool.

It may bring you some surprises too. I discovered an old Spotlight metadata importer which was not just 32-bit Intel, but a Fat Binary with 32-bit PowerPC support as well!


ArchiChect version 1.0b2*, which should run on macOS Sierra, High Sierra and Mojave, is now available from here: archichect10b2
and from Downloads above.

I hope that you find it as useful as I have already.

If you have any additional features which you want me to consider for inclusion, please let me know by comment below. Once I have sorted this Open bug out, and any others which arise during testing, I’d like to add a Help book and release it. I think many of us need it now.


Version 1.0b2, as provided now, should (fingers crossed) be compatible with Sierra and later, and fixes the crashing bug reported in the comments below. Thanks to testers for your help.