@scottearle Because Apple has been making some really bad decisions in Tahoe. See https://mjtsai.com/blog/2025/08/08/separate-icons-for-macos-tahoe-vs-earlier/#separate-icons-for-macos-tahoe-vs-earlier-update-2025-09-10
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@siracusa Can you make a last-version of your app that is marked as compatible with Pre-Tahoe, and then make a new version of your app that is only available Tahoe+?
(only applies if you're talking about an app that deploys through the AppStore(s))
@fbartho Not if I ever want to update the version for pre-Tahoe ever again (and I do).
I pushed Claude to find a solution. It made a heroic effort, trying many different approaches. But in the end, it did not find a solution.
I gave Codex a shot at the problem in Xcode 26.3, but it also failed to find a solution. Then I rubber-ducked with it for a while and came up with a new, terrible approach:
1. Copy the Assets.car file from a build of my app made with Xcode 26.0.1 into the repo.
2. Add a new build phase that replaces the built Assets.car with the saved "good" Assets.car file.
It works! But I need to use Xcode 26.0.1 or earlier if I ever want to change my icon.
Apple, please, end this madness. FB19437407
![The new build step I added to my project:
set -e
SOURCE_CAR="${PROJECT_DIR}/SwitchGlass/BuildResources/Assets.car"
DEST_RESOURCES="${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}"
if [ -f "$SOURCE_CAR" ]; then
/bin/cp -f "$SOURCE_CAR" "${DEST_RESOURCES}/Assets.car"
fi
/usr/libexec/PlistBuddy -c "Delete :CFBundleIconFile" "${TARGET_BUILD_DIR}/${INFOPLIST_PATH}" >/dev/null 2>&1 || true
/bin/rm -f "${DEST_RESOURCES}/AppIcon.icns"](https://files.mastodon.social/media_attachments/files/116/013/242/389/795/284/original/7deef0979815b082.png)
@siracusa It strikes me that you’re battling against Apple’s institutional delusion that newOS is best, and everyone should be on it. As consequence, they DGAF about issues with oldOS.
@siracusa Curious if we could write a quick utility that could inject those settings into each new Assets.car so we at least wouldn’t have to keep Xcode 26.0.1 around.
@timoliver It’s more about stripping stuff out of Assets.car. It’s surely possible, but I don’t know how to do it, and Calude and Codex also couldn’t figure it out.
The summary of this hack is to make the .app built by Xcode 26.3 look like the .app built by Xcode 26.0.1 using this approach: https://mastodon.social/deck/@siracusa/115254777896289996
To do this: use the copied Assets.car, make sure the Info.plist icon stuff matches, and delete any built .icns files that the Xcode 26.0.1-built version doesn't have.
Another possible approach is to use the version of actool that came with Xcode 26.0.1, which honors the --enable-icon-stack-fallback-generation=disabled option (unlike the version in Xcode 26.1 and later), but copying the Assets.car file wholesale seemed simpler.
@siracusa I'm just going to throw a crazy idea into the mix. Is it possible to write a small supplemental app that "copies and pastes" a different icon if you're on an older OS? Like, QuitchGlass, but for icons. Maybe it runs and checks at startup? I know it's stupid, but maybe it leads to a better solution.
@marcintosh Getting people to find, download, and install that would be difficult.
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@siracusa Why can’t this all be straightforward?
@scottearle Because Apple has been making some really bad decisions in Tahoe. See https://mjtsai.com/blog/2025/08/08/separate-icons-for-macos-tahoe-vs-earlier/#separate-icons-for-macos-tahoe-vs-earlier-update-2025-09-10
@siracusa it’s odd really. I find iOS 26 to be … fine. But Tahoe is a hot mess.
The best of the bunch has to be tvOS - the interface gets in the way a lot less
Oh, is this why I’m seeing Tahoe icons even though I’m not using Tahoe
@siracusa My current 'solution' is to stick with Xcode 26.0.1.