A set of .NET Framework managed libraries for developing graphical user interfaces.
Hello @Martin Deleu , and thank you for reaching out.
The error message indicates that the Windows Forms Designer could not load the form, but it doesn't identify the underlying cause.
To help narrow down the issue, could you share the following information?
- Your Visual Studio version, project template, and target framework.
- The full error details shown by the designer, if available.
- Whether the same issue occurs when creating a new Windows Forms project.
In the meantime, you can try the following steps:
- Clean and rebuild your solution, then check whether any errors appear in the Error List.
- If the issue persists, close Visual Studio, delete the project's
binandobjfolders, then reopen and rebuild the solution.
You can also refer to the Windows Forms Designer error documentation for additional troubleshooting guidance.
If you found my response helpful or informative, I would greatly appreciate it if you could follow this guide for your confirmation. Thank you.