Fixes

Error messages, decoded: the exact text you searched for, what it actually means, the fix, and where it bit us in a real build.

NETSDK1147: To build this project, the following workloads must be installed: maui-android

Your CI installed the android workload and the MAUI build still fails with NETSDK1147. A MAUI project needs maui-android: one word, and why the bare workload isn't enough. Sep 4, 2026 2 min read

NU1102 on dotnet publish -r win-x64 for a MAUI app: NuGet can't find a Mono runtime pack

Publishing a multi-target MAUI project with -r win-x64 makes NuGet restore every target for that runtime, and Android's Mono runtime has no win-x64 pack. Drop the flag. Sep 4, 2026 2 min read

MSB3030: Could not copy the file: a Windows App SDK build that dies past MAX_PATH

The Android target builds, the Windows target fails on a copy step with a very long file name. The cause is your folder path, not your project: Windows' 260-character MAX_PATH. Sep 4, 2026 2 min read

D8: Type androidx.fragment.app.FragmentKt is defined multiple times (MAUI + Firebase)

Adding Xamarin.Firebase.Messaging to a .NET MAUI app breaks the Android build with a duplicate FragmentKt. Two versions of fragment-ktx are on the classpath: pin one. Sep 4, 2026 2 min read

Blazor Hybrid on Android: content hidden under the status bar, env(safe-area-inset-top) is 0

Your header sits under Android's status bar and the CSS safe-area variables read zero inside the WebView. The insets have to come from the native side; here's the listener. Sep 4, 2026 2 min read

MAUI Android: 'No maps app' or ActivityNotFoundException with Google Maps installed

Map.Default.TryOpenAsync returns false and your app reports no maps app, even though Google Maps is right there. Android 11's package visibility rules need a queries block in your manifest. Sep 4, 2026 2 min read

postgres:18 Docker container exits immediately: mount the volume at /var/lib/postgresql

Your compose file worked for years and the postgres:18 image now stops on start. The data directory moved; the old /var/lib/postgresql/data mount is the problem. Sep 4, 2026 2 min read

Blazor serves empty CSS and JS files: MapStaticAssets without ASPNETCORE_ENVIRONMENT=Development

The page renders like 1996 and every static file comes back with zero bytes. dotnet run --no-launch-profile means Production, and MapStaticAssets wants published assets there. Sep 4, 2026 2 min read

SignalR WithAutomaticReconnect() stops reconnecting after four attempts

The server came back a minute ago and the client still says reconnecting. The default policy retries at 0, 2, 10 and 30 seconds and then closes for good; a custom IRetryPolicy fixes it. Sep 4, 2026 2 min read

Firebase says '1 delivered' but Android shows nothing: adb force-stop puts your app in stopped state

Testing push to a closed app with am force-stop guarantees silence: Android never delivers FCM to a force-stopped app. Simulate a real close with HOME and am kill instead. Sep 4, 2026 2 min read

CS0104: 'View' is an ambiguous reference between Android.Views.View and Microsoft.Maui.Controls.View

One line of Android insets code in a MAUI project and the compiler can't tell which View you mean. The one-token fix, and the using-alias alternative for files that need both. Sep 4, 2026 2 min read

dotnet build fails because the DLL is locked: your app (or test host) is still running

MSB3027 and MSB3021: could not copy, the file is being used by another process. It's your own server from the last dotnet run. How to find it, stop it, and stop hitting this. Sep 4, 2026 2 min read

ASP.NET Core: 'Unable to resolve service for type IOutputCacheStore', and why .CacheOutput() alone caches nothing

UseOutputCache without AddOutputCache throws at startup; .CacheOutput() on its own starts fine and silently caches nothing. The two mistakes, the one-line fixes, and when a Cache-Control header is enough. Sep 4, 2026 2 min read

CS0104: 'BarcodeReader<T>' is ambiguous between ZXing.Net and ZXing.Net.Bindings.ImageSharp

Both ZXing packages define a BarcodeReader<T> in overlapping namespaces. The fully-qualified fix, and which one you actually want for decoding a PNG in a test. Sep 4, 2026 2 min read

AppNotificationManager.Show() displays no toast on Windows: the unpackaged-app identity problem

Register() succeeds, Setting is Enabled, Show() returns, and nothing appears. Unpackaged WinUI and MAUI apps have no identity Windows will toast for. What would fix it, and why this season never proved it. Sep 4, 2026 2 min read

MAUI SecureStorage.GetAsync throws on Android after a keystore reset

A value that saved fine yesterday throws on read today. Android's keystore invalidated the key and SecureStorage can't decrypt. Catch it, treat the value as gone, and clear the store if you want a clean slate. Sep 4, 2026 2 min read

EF Core: two HasIndex calls on the same column create only one index (name them)

You configured a unique filtered index and a plain index on the same property and the migration contains one. EF merges same-property HasIndex calls unless each has a name. Sep 4, 2026 2 min read

dotnet run -nologo: the switch lands in your application's args

MSBuild switches after dotnet run are forwarded to your app, so -nologo becomes args[0]. Why a screenshot harness then photographed a directory listing, and where MSBuild flags actually go. Sep 4, 2026 2 min read

apksigner verify prints a valid signature but your script reports failure: it is the shell, not apksigner

apksigner.bat returns Java's exit code, and that is 0 on success. The failure reading came from the calling shell: an early-stopping PowerShell pipeline and redirected stderr. How to read the result correctly. Sep 4, 2026 2 min read

Blazor: the h1 shows a focus ring after navigation (FocusOnNavigate and tabindex=-1)

FocusOnNavigate moves keyboard focus to your heading for accessibility, and your :focus-visible rule draws a ring around it. Keep the focus, lose the ring, without harming keyboard users. Sep 4, 2026 2 min read

CS0542: member names cannot be the same as their enclosing type (a Blazor @inject named after its page)

Queue.razor compiles to a class called Queue, so injecting a member called Queue is illegal. Rename the injected property, not the page. The AI made the identical mistake twice. Sep 4, 2026 2 min read

EF Core: 'The model for context has pending changes' in tests while the app migrates fine

Options resolved from dependency injection shape the EF model. A test fixture that builds DbContextOptions without Identity's SchemaVersion builds a different model than the app and fails the snapshot check. Sep 4, 2026 2 min read

ASP.NET Identity 'Invalid login attempt' with the right password: RequireConfirmedAccount and seeded users

The template requires a confirmed account and ships no email sender, so seeded logins return NotAllowed, which the login page reports as a wrong password. Turn the setting off, or seed EmailConfirmed = true. Sep 4, 2026 2 min read

Blazor: 'An unhandled error has occurred' shows on every page after deleting the template CSS

The error banner is always in the layout markup and only hidden by a display:none rule in MainLayout.razor.css. Delete the template stylesheet and the banner greets every visitor with no error at all. Sep 4, 2026 2 min read

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