After I close the first Office window for Word (the one giving the option to open a new document) I now find that blank Word documents have been opened displaying a box telling me that.....

We couldn't find https://d.doc.live.net/xxxxxxxxxxxxx...ocument21.docx

I have no idea what this means.

Where is https://d.doc.live.net/xxxxxxxxxxxxxxxxxxxx located?

I have checked Onedrive and Document21.docx exists in there!