If the file does not open readily it is usually because the file extension is not known, the file is corrupt, the file is too large, or the file program is not loaded.
I would right click this item and try to save to your desktop. If you are able to open it then, great.
Do you have this problem with other word documents? Is a colleague able to open it? Do you have this problem with other formats (e.g. xlsx, pdf.).