Calibre see's OPF file as a book when importing books

[userpaul]

Hi
I recently built a new pc Windows 10 Build 17763 and copied my libraries to one of my new HDD's, downloaded the latest 64bit Calibre and attempted to load one of the libraries. Calibre did not recognise the original Folder as a library. No problem I thought I will just reimport the books.
Add Books - Add books from directories and sub directories - Multi file books -Option NO

Calibre sees some of the OPF files as books and does the following: -
1 Creates a folder with an OPF file and Cover.
2 Creates a folder with a Book, Cover and OPF file.
There is no obvious selection to this some have the original book in, and some have the OPF file instead. So, when the import is complete I am presented with an option to select / not select the duplicate books. Calibre has a duplicate entry for every book in my original library.
If I select not to import duplicates I'm left with a library where approximately 50% of the folders have an OPF file rather than a book. Conversly if I select import duplicates I get double the number of books but only half the folders actually have a book in.
Perhaps I'm doing something stupid?
I have attached images
Any help would be appreciated.

Paul

[kovidgoyal]

You need to click yes on the dialog that says assume all ebook files in the directory are the same book in different formats.

[userpaul]

Originally Posted by kovidgoyal

You need to click yes on the dialog that says assume all ebook files in the directory are the same book in different formats.

Thank you

That worked