Starting with version 16.2.0.x, you must register a license key in your application code (usually in Program.cs or the main Form constructor) to remove trial watermarks.
If you are looking for Syncfusion WinForms controls without the high enterprise cost, there are legitimate ways to get them: Syncfusion Community License : Syncfusion offers a syncfusion winforms crack verified
For developers seeking to verify their Syncfusion WinForms licenses or troubleshoot licensing issues, we recommend the following verified methods: Starting with version 16