iOS 27: system-wide registered fonts disappear from Settings > General > Fonts after every reboot

Question

Created 5d

Replies 1

Boosts 0

Participants 1

Hello, We ship a font provider app that installs fonts system-wide on iOS, delivering the font files through On-Demand Resources. Since iOS 27 shipped, customers have been reporting that their installed fonts vanish from the system font list after every restart. I would like to know whether the restore path for system-wide font registrations changed in iOS 27, and what a font provider app is expected to do after a device reboot. Environment

iOS 27.0 and 27.0.0 only. We have no reports on iOS 26 or earlier.
iPhone 18 Pro and iPhone 18 Pro Max
Fonts delivered through On-Demand Resources and registered for system-wide installation using CoreText

Steps to reproduce

Activate a font in the app. It appears in Settings > General > Fonts.
Reboot the device.
Without launching the app, open Settings > General > Fonts. The font is gone.
The app still shows the font as active, because it keeps its own activation state.
Deactivate and reactivate the font in the app. It comes back.
Reboot again. It disappears again.

This happens on every reboot. It also happens with a single font activated, and it persists after updating or reinstalling the app. Because the font is missing from the system font list, it is also missing in other apps that use system fonts. What we have ruled out

Not low storage. These are new devices with plenty of free space. The documented purge trigger for On-Demand Resources is low storage, which does not explain a result this consistent.
Not a crash. Our crash data for the affected app version shows no elevated crash rate on iOS 27 compared to iOS 18.
Not specific to one font or one app version.

Questions

Did the restore path for system-wide font registrations change in iOS 27? Are registrations that reference files inside On-Demand Resources still restored at boot?
If a font provider app now has to re-register after a reboot, when and how should it do that? There is no natural launch point, since someone may use the font in another app without opening ours first.
Is there a supported way for the app to detect that a font it installed is no longer present in the system font list, so it can repair the registration quietly?

Context We deliver several thousand fonts this way, and Apple increased our On-Demand Resources limit for that reason (Case-ID 17273913, December 2025). On-Demand Resources is deprecated as of iOS 27. We have separately confirmed that fonts delivered through Background Assets cannot be registered system-wide: registration fails with CTFontManagerErrorDomain code 306, both from the Background Assets container and after copying the files into the app sandbox, because CoreText requires the file to sit inside the app bundle or On-Demand Resources. We have a separate question open about that migration path, so this post is only about the reboot behavior on iOS 27. Happy to provide a sysdiagnose from an affected device and a sample project. Thank you.

Answer 1

launzi OP

2d

Follow-up with what we've learned since the original post.

Updated scope

16 customer reports so far, all on iOS 27.0. Devices are mostly iPhone 18 Pro and 18 Pro Max, plus one iPhone 17. We also reproduce it on an iPhone Air in our office.
Five customers say it started right after they moved to a new iPhone. Two of them say they never saw it on their previous phone (an iPhone 14 Pro and an iPhone 15 Pro). It also happens with free fonts, so it isn't tied to purchases.
We cannot reproduce it on an iPhone 14 Pro, either on iOS 27.0 or on iOS 27.2 beta (24B5084k). We rebooted the 14 Pro twice with the font active, once with English as the primary language and once with Korean, and the font stayed both times.
Registration call, to fill in the gap in my first post: CTFontManagerRegisterFontURLs with kCTFontManagerScopePersistent, on font file URLs inside On-Demand Resources asset packs. The app has the com.apple.developer.user-fonts entitlement with app-usage and system-installation.

Two more details

After the reboot, our app still shows the fonts as installed, but the system no longer has them. Settings, Kakao Talk and other apps don't see them, and relaunching our app doesn't bring them back. The only way back is to reactivate the font in our app.
On our iPhone Air, reactivating shows the first-time font installation consent prompt again. It looks as if the system forgot our app as a font provider, not just the individual fonts. That's hard to explain with an On-Demand Resources purge, which shouldn't reset the provider consent.

What we think is happening

We compared fontservicesd across the iOS 26.6.2, 27.0 and 27.2 beta restore images. At launch, it checks every known font provider by looking up its bundle identifier with LSApplicationRecord (allowPlaceholder:NO, no error handling). If that lookup returns nil, it logs stray provider "%@" detected, unregisters that provider's fonts, deletes the copies under UserFonts, and forgets the provider.

This matches all three symptoms: fonts gone from Settings and other apps, our app still thinks they're active, and the consent prompt comes back. The code is the same in 26.6.2, 27.0 and 27.2 beta, so our guess is that the LaunchServices lookup fails early in boot on newer devices. That would explain why we only see it on current hardware. We haven't been able to confirm this from device logs, because the message bodies are redacted as <private> and there's no Apple-signed logging profile for FontServices or LaunchServices.

Questions

Can you confirm whether the stray provider check in fontservicesd can remove a provider that's still installed, if LaunchServices isn't ready or returns an error at that moment?
If so, is there anything a font provider app can do to avoid it? Right now our only option is to detect the missing fonts when the user opens our app and ask them to reactivate, which means going through the consent prompt again after every reboot.
Is there a logging profile, or another way, to see the unredacted FontServices and LaunchServices messages on a customer device? That would let us send you a log from an affected device showing the exact path.

Since the check is unchanged in 27.2 beta, we expect this to continue after 27.2 ships. Happy to provide more if it helps.

Thanks.