Syncfusion Trial License Key Fix -

You must register the key before any Syncfusion control is rendered. The best place is in your application's entry point.

For ASP.NET Core / Blazor (Program.cs):

using Syncfusion.Licensing;
var builder = WebApplication.CreateBuilder(args);
// THE FIX: Register your key here
SyncfusionLicenseProvider.RegisterLicense("YOUR_LICENSE_KEY_HERE");
builder.Services.AddRazorPages();
// ... rest of your code
 syncfusion trial license key fix

For Windows Forms / WPF (.NET Framework / .NET Core):

// In Program.cs (Main method) or App.xaml.cs constructor
using Syncfusion.Licensing;
static void Main()
SyncfusionLicenseProvider.RegisterLicense("YOUR_LICENSE_KEY_HERE");
Application.Run(new Form1());

For Xamarin / MAUI (App.xaml.cs):

public App()
Syncfusion.Licensing.SyncfusionLicenseProvider.RegisterLicense("YOUR_LICENSE_KEY_HERE");
    InitializeComponent();

Syncfusion has a known issue where the trial key expiration is cached at the machine level. Fix it like this:

This is where most people fail. You must register before any Syncfusion control is referenced or created.

For .NET Core / .NET 5+ (Web Apps, Blazor, WinForms): In Program.cs, right after CreateHostBuilder or at the top of Main: You must register the key before any Syncfusion

public static void Main(string[] args)
// MUST be first line inside Main
    Syncfusion.Licensing.SyncfusionLicenseProvider.RegisterLicense("YOUR_TRIAL_KEY_HERE");
CreateHostBuilder(args).Build().Run();

For legacy .NET Framework (WinForms, WPF): In App.xaml.cs (WPF) or Program.cs (WinForms), inside the constructor or OnStartup:

public App()
Syncfusion.Licensing.SyncfusionLicenseProvider.RegisterLicense("YOUR_TRIAL_KEY_HERE");

For Blazor WebAssembly (client-side): In Program.cs (of the client project), right after using statements and before await builder.Build().RunAsync();: For Windows Forms / WPF (

Syncfusion.Licensing.SyncfusionLicenseProvider.RegisterLicense("YOUR_TRIAL_KEY_HERE");