Weird behaviour

[vicmosin]

I do have version 3.0.4 (at avalonia app):

_sparkle = new SparkleUpdater(
    "https://storage.example.org/appcast.xml", 
    new Ed25519Checker(NetSparkleUpdater.Enums.SecurityMode.Strict, "SECRET")
)
{
    RelaunchAfterUpdate = true,
    CustomInstallerArguments = "/S"
};
_sparkle.UpdateDetected += async (s, e) =>
{
    if (_updateInProgress) return;
    _updateInProgress = true;

    await Dispatcher.UIThread.InvokeAsync(async () =>
    {
        var item = e.AppCastItems[0];
        var vm = new UpdateViewModel(_sparkle, item);
        var dialog = new UpdateDialog();
        vm.ParentWindow = dialog;
        dialog.DataContext = vm;
        await dialog.ShowDialog(this);
        vm.Dispose();

        if (!vm.IsInstalling)
        {
            _updateInProgress = false;
        }
    });
};
await _sparkle.StartLoop(true, true);

On most of the computers works fine but there is one which almost always fails:

24.04.2026 15:16:56 : [Autoupdate] Starting update process
24.04.2026 15:17:01 : [Autoupdate] Download finished: C:\Users\XXX\AppData\Local\Temp\Update_2.0.46.exe
24.04.2026 15:17:01 : [Autoupdate] Preparing to exit
24.04.2026 15:17:23 : [Autoupdate] Starting update process
24.04.2026 15:17:23 : [Autoupdate] Download started: C:\Users\XXX\AppData\Local\Temp\Update_2.0.46.exe
24.04.2026 15:17:49 : [Autoupdate] Download error: Downloaded file has invalid signature!
UpdateViewModel OnDownloadHadError 0
SparkleUpdater OnDownloadFinished 0
<StartFileDownloadAsync>d__36 MoveNext 0
AsyncStateMachineBox`1 ExecutionContextCallback 0
24.04.2026 15:18:21 : [Autoupdate] Cancelling update process

From user perspective it looks like the dialog is shown and update is being confirmed by user. Then it tries to restart the app but later comes another attempt to download the file (no user interaction involved here) and it fails with signature.
Any ideas?

[Deadpikle]

Hi @vicmosin,

I'm not sure exactly what's going on, but there's a few things I've noticed that could perhaps lead to such behavior:

• You're using UpdateDetected but then make it async. You should be using UpdateDetectedAsync.
• The event in UpdateDetected should have its NextUpdateAction set. It looks like you're trying to show your own dialog instead of the built-in items...? You need to be rolling your own UIFactory so you can control the UI yourself because right now you've got some mix of NetSparkle controlling things and your own app user doing things in your own UI. Your user may be seeing two update dialogs and getting confused.