Unfortunately it cannot open .mov files directly. You should try this: "File" -> "Open Video File" In the dialog box, select "files of type" as "DirectShow input driver". Select mov file (If you cannot see .mov files, enter *.* or *.mov in the "File Name" field) and open it. Then, "File" -> "Save as Avi"
This should work.
For the purpose of converting .mov files, I've been using AppGeeker video converter (no any add-ons) for many years.