EDIT 2021-10-20: Latest C-Pen Core requires .NET 4.7.2
NOTE: .NET 4.8 is backwards compatible with 4.7.2

Just installed C-PEN Core and it does not start properly?

Is there a “.NET missing” error message?


.NET is a Windows component used by C-PEN Core software, the Windows software to use with e.g. our TS1 models. In Windows 10, .NET 3.5 does not always come preinstalled which will cause this error. To resolve it – .NET 3,5 needs to be installed manually.


The video below shows the step.




  1. Open Control Panel
  2. Go To Programs
  3. Select Turn Windows Components On Or Off
  4. Locate .NET 3.5 and make sure the check box is checked.
  5. NEW: Locate .NET Framework 4.8 and make sure the box is checked.
  6. Click Apply/OK to install.


Now get back and try to restart C-PEN Core.