Open Visual Studio and click Build > Rebuild Solution . Troubleshooting Checklist
Open Program.cs (WinForms) or App.xaml.cs (WPF) and register the license in the main entry point:
If using the Community License, is your account still eligible and the key refreshed for the current year? syncfusion trial license key fix
To help me tailor the next step, could you tell me you are developing on, and the exact version number of the Syncfusion packages you have installed? Share public link
Open your main.dart file and add the registration inside the main() function: Open Visual Studio and click Build > Rebuild Solution
The core registration code is almost identical across all .NET platforms:
: Clean the solution and manually delete the bin and obj folders. Share public link Open your main
Syncfusion moved to a several years ago. Unlike older components that relied on MSI installers to validate your machine, modern Syncfusion libraries (ASP.NET Core, Blazor, Flutter, React, etc.) require a programmatic key registration within your code. The warning persists usually because: The license key is missing from your startup logic.
Are you seeing a "Syncfusion license key is invalid" watermarked message or encountering runtime exceptions in your application? This usually happens when the trial license key is missing, registered incorrectly, or mismatched with your installed product version.
No, the application will usually continue to run, but it will display disruptive trial watermarks, popups, or console warnings. To remove these visual blockers, you must generate a new key or purchase a commercial license.
I can provide the exact code block or targeted troubleshooting steps for your setup. Share public link