NetBeans IDE as a GUI Design Tool

I use NetBeans IDE to develop a Java application. In the past, I could use the Design Editor to edit my form for the GUI. Spontaneously, NetBeans is unable to open the form file, producing this pop-up message labled as "Information": "The form file format is not recognized. The form cannot be opened."

This error was allegedly fixed in previous versions of NetBeans. I have the latest version of NetBeans and I am getting this error now, which drastically limits the viability of NetBeans as an IDE. Does anyone have experience with this error? Please let me know if you have any information, anything is appreciated.