NewForm.aspx disappeared

Question

In SharePoint online the calendar default new form disappeared, and whenever I try to create a new one I keep getting:

I have tried clearing the SharePoint designer cache but I keep facing the same problem - any solutions out there for me to get my default newform back?

Answer 1

1. Open the site in SharePoint designer . Then Open the NewForm.aspx of the list and checkout it.
2. Then add ListFormWebPart on to the page. Insert->SharePoint Controls->List Form.
3. Save it. Right click on the newform.aspx in the explorer and create new from existing page.
4. Make the new file as the new display form. Right click on the list->Properties->Supporting files. Then select newly created page in the first textbox.
5. Now delete the old newform.aspx and rename the new one to NewForm.aspx.