Problem adding ebooks to Calibre

I have recently had problems when adding ebooks to Calibre via the Add Books button. When I press this, the Select Books dialog appears and within a few seconds, I get an error messagesaying that "The calibre-file-dialog.exe has stopped working". alibre then shows an "ERROR: Unhandled exception" box saying that "Exception:file dialog failed(return code -1073741819)".

Any thoughts on the cause and what I can do to fix? So far it seems that Calibre is working normally. I am using V2.80.0.