UnoSdk 6.5: Android: "Failed to load icuuc." fatal exception at launch

[baskren]

Current behavior 🐛

Setup:

• New Uno.WinUI app from https://new.platform.uno
• UnoSdk 6.5 (no issue with 6.4)
• Build and run app, the following exception occurs during launch:

Outer Exception

03-03 18:35:48.663 D/AndroidRuntime(25366): Shutting down VM
03-03 18:35:48.664 E/AndroidRuntime(25366): FATAL EXCEPTION: main
03-03 18:35:48.664 E/AndroidRuntime(25366): Process: com.companyname.newa, PID: 25366
03-03 18:35:48.664 E/AndroidRuntime(25366): android.runtime.JavaProxyThrowable: [System.Reflection.TargetInvocationException]: Exception has been thrown by the target of an invocation.
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at System.Reflection.MethodBaseInvoker.InvokeConstructorWithoutAlloc + 0x10a(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at System.Reflection.RuntimeConstructorInfo.Invoke + 0x50(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at System.Reflection.MethodBase.Invoke + 0x0(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at Java.Interop.TypeManager.CreateProxy + 0x22(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at Java.Interop.TypeManager.CreateInstance + 0x271(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at Android.Runtime.AndroidValueManager.CreatePeer + 0xa(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at Java.Interop.JniRuntime+JniValueManager.GetPeer + 0x48(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at Java.Lang.Object.<GetObject>g__GetPeer|29_0 + 0x0(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at Java.Lang.Object.GetObject + 0xa(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at Java.Lang.Object._GetObject + 0x12(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at Java.Lang.Object.GetObject + 0x0(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at Java.Lang.Object.GetObject + 0x6(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at Android.App.Application.n_OnCreate + 0xe(Unknown Source)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at crc64d0916be76e7aa092.NativeApplication.n_onCreate(Native Method)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at crc64d0916be76e7aa092.NativeApplication.onCreate(NativeApplication.java:24)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:1182)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at android.app.ActivityThread.handleBindApplication(ActivityThread.java:6460)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at android.app.ActivityThread.access$1300(ActivityThread.java:219)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1859)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at android.os.Handler.dispatchMessage(Handler.java:107)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at android.os.Looper.loop(Looper.java:214)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at android.app.ActivityThread.main(ActivityThread.java:7356)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at java.lang.reflect.Method.invoke(Native Method)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
03-03 18:35:48.664 E/AndroidRuntime(25366): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

When looking at stack trace in debugger, see the following:

Inner Exception

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
 ---> System.TypeInitializationException: The type initializer for '<Module>' threw an exception.
 ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
 ---> System.Exception: Failed to load icuuc.
   at Microsoft.UI.Xaml.Documents.UnicodeText.ICU.Init() in C:\a\1\s\src\Uno.UI\UI\Xaml\Documents\UnicodeText.ICU.skia.cs:line 95
   at Microsoft.UI.Xaml.Documents.UnicodeText.ICU.SetDataAssembly(Assembly assembly) in C:\a\1\s\src\Uno.UI\UI\Xaml\Documents\UnicodeText.ICU.skia.cs:line 34
   at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
   at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)
   --- End of inner exception stack trace ---
   at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)
   at System.Reflection.MethodBaseInvoker.InvokeWithOneArg(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters)
   at __IcuDataInitializer.Initialize() in /Users/ben/Development/Uno/NewA/NewA/obj/Debug/net10.0-android/android-arm64/Uno.UI.SourceGenerators/Uno.UI.SourceGenerators.IcuDataInitializerGenerator/IcuDataInitializer.g.cs:line 9
   at <Module>..cctor()
   --- End of inner exception stack trace ---
   at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Constructor(Object obj, IntPtr* args)
   at System.Reflection.MethodBaseInvoker.InvokeConstructorWithoutAlloc(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   --- End of inner exception stack trace ---
   at System.Reflection.MethodBaseInvoker.InvokeConstructorWithoutAlloc(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.RuntimeConstructorInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters)
   at Java.Interop.TypeManager.CreateProxy(Type type, IntPtr handle, JniHandleOwnership transfer)
   at Java.Interop.TypeManager.CreateInstance(IntPtr handle, JniHandleOwnership transfer, Type targetType)
   at Android.Runtime.AndroidValueManager.CreatePeer(JniObjectReference& reference, JniObjectReferenceOptions options, Type targetType)
   at Java.Interop.JniRuntime.JniValueManager.GetPeer(JniObjectReference reference, Type targetType)
   at Java.Lang.Object.<GetObject>g__GetPeer|29_0(IntPtr handle, Type type)
   at Java.Lang.Object.GetObject(IntPtr handle, JniHandleOwnership transfer, Type type)
   at Java.Lang.Object._GetObject[Application](IntPtr handle, JniHandleOwnership transfer)
   at Java.Lang.Object.GetObject[Application](IntPtr handle, JniHandleOwnership transfer)
   at Java.Lang.Object.GetObject[Application](IntPtr jnienv, IntPtr handle, JniHandleOwnership transfer)
   at Android.App.Application.n_OnCreate(IntPtr jnienv, IntPtr native__this)

Expected behavior 🎯

No exception throw (as was in UnoSdk 6.4)

How to reproduce it (as minimally and precisely as possible) 🔬

Demo Repo: https://github.com/baskren/UnoAndroidL-Failed-to-load-icuuc.git

• App created using : dotnet new unoapp -o NewApp -preset "recommended"

Workaround 🛠️

Revert back to UnoSdk 6.4

Renderer 🎨

• Skia
• Native

Affected platforms 📱💻🖥️

Android

Uno.Sdk version (and other relevant versions) 📦

UnoSdk: 6.5

IDE version 🧑‍💻

JetBrains Rider 2025.3.3

Build #RD-253.31033.136, built on February 19, 2026 Source revision: 565764487c99e Licensed to Benjamin Askren Subscription is active until January 12, 2027. For educational use only. Runtime version: 21.0.10+7-b1163.108 aarch64 (JCEF 137.0.17) VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o. Toolkit: sun.lwawt.macosx.LWCToolkit macOS 26.3 .NET Core v9.0.11 ARM64 (Server GC) GC: G1 Young Generation, G1 Concurrent GC, G1 Old Generation Memory: 8192M Cores: 12 Metal Rendering is ON Registry: ide.lookup.shrink=true ide.experimental.ui=true rider.codeVision.fitToContent.enabled=true find.in.files.split.actions=false llm.show.ai.promotion.window.on.start=false find.in.files.split=false rider.codeVision.zeroWidth.preload.enabled=true Non-Bundled Plugins: org.antlr.intellij.plugin (1.25) com.intellij.resharper.HeapAllocationsViewer (2025.3.0) lermitage.intellij.iconviewer (1.32.1) com.redhat.devtools.lsp4ij (0.19.2) com.jetbrains.rider.android (253.31033.136) com.github.camork.fileExpander (2.5) com.wakatime.intellij.plugin (15.0.4) unoplatform (1.9.13) fr.socolin.awesomeLogViewer (2025.3.1) com.jetbrains.sqlproj (0.1.12) me.rafaelldi.aspire (1.9.5) com.intellij.resharper.azure (4.6.5)

Android/JDK Info

Anything else we need to know? 💬

No response

[ezesil]

Same here. Version 6.5.31. I'm leaving logs from adb logcat:

adb logcat | findstr -i icu

03-04 20:45:18.613 1532 1532 V AconfigFlags: Read Aconfig default flag value com.android.icu.icu74 = false
03-04 20:45:18.613 1532 1532 V AconfigFlags: Read Aconfig default flag value com.android.icu.icu_v_api = true
03-04 20:45:19.341 1532 1532 V AconfigFlags: Read Aconfig default flag value com.android.text.flags.icu_bidi_migration = true
03-04 20:45:19.781 1532 1532 V AconfigFlags: Read Aconfig default flag value com.android.icu.icu74 = false
03-04 20:45:19.781 1532 1532 V AconfigFlags: Read Aconfig default flag value com.android.icu.icu_v_api = true
03-04 20:45:19.868 1532 1532 V AconfigFlags: Read Aconfig default flag value com.android.text.flags.icu_bidi_migration = true
03-04 20:45:28.586 1865 1947 I ContactsDatabaseHelper: Switching to locale [en_US] (ICU v75.1.0.0)
03-04 20:45:28.628 1865 1947 I ContactsDatabaseHelper: Switching to locale [en_US] (ICU v75.1.0.0)
03-04 20:45:32.616 1714 2297 V AconfigFlags: Read Aconfig default flag value com.android.text.flags.icu_bidi_migration = true
03-04 20:45:34.204 1714 2297 V AconfigFlags: Read Aconfig default flag value com.android.icu.icu74 = false
03-04 20:45:34.204 1714 2297 V AconfigFlags: Read Aconfig default flag value com.android.icu.icu_v_api = true
03-04 20:45:34.256 1714 2297 V AconfigFlags: Read Aconfig default flag value com.android.text.flags.icu_bidi_migration = true
03-04 20:46:29.908 529 1202 D mediaserver: u_setTimeZoneFilesDirectory("/apex/com.android.tzdata/etc/tz/versioned/8/icu") succeeded.
03-04 20:46:29.909 529 1202 D mediaserver: I18n APEX ICU file found: /apex/com.android.i18n/etc/icu/icudt75l.dat
03-04 20:50:34.100 6490 6490 W monodroid-assembly: Shared library 'unoicu' not loaded, p/invoke 'init_line_breaker' may fail
03-04 20:50:34.104 6490 6490 W monodroid-assembly: Shared library 'unoicu' not loaded, p/invoke 'next_line_breaking_opportunity' may fail
03-04 20:55:08.647 8892 8892 W monodroid-assembly: Shared library 'unoicu' not loaded, p/invoke 'init_line_breaker' may fail
03-04 20:55:08.652 8892 8892 W monodroid-assembly: Shared library 'unoicu' not loaded, p/invoke 'next_line_breaking_opportunity' may fail

Then it simply crashes.

Hope this helps. I'm reverting to 6.4.26 for now.