The document could not be created. The required application may not be installed properly, or the template for this document library cannot be opened.

Working within my VM this morning, and just testing out basic functionality of SharePoint on my demo site. I went to do a very simple task of creating a new document. I received the following pop up.

It took me a moment, but I realised I didn’t have any Office products installed on my VM, however I did have Office Web Apps. I thought I should still be able to create a new document. It turns out that if you disable an Internet Add-On this message goes away. The Internet Add-On is called SharePoint OpenDocuments Class, (which sounds like it needs to be enabled for it to work!)

As soon as I disabled it, without any browser restart, I was able to create a new document.