Hi,
First apologies for the delay in getting back to you. Another long and busy day at work.
Changing the media folder listed in iTunes preferences tells iTunes where to put new media that is added to the library. It won't make an empty library detect the media in that folder. iTunes does't generally like you to move content around by hand, but there are certain changes that can be made which won't break existing connections to the media. These are set out in Make a split library portable. If the library is already full of broken links then it may be a good move to manually create the standard layout before trying other techniques to repair broken links, but I wouldn't start there. Your library is not only the sum of all the files in the media folder, but also various other bits of information such as ratings, play counts, playlists, date added values and other metadata not captured in the tags. Restoring or connecting to an older library file should bring back this data. There are tips to get the library file updated with any new content added since the database was archived.
So, it would seem that ..\Music\iTunes\Previous iTunes Libraries\iTunes Library 2016-09-26.itl is the newest .itl file that you have. This makes a degree of sense. The last update that made a change to the database was 12.5.1 back in September. iTunes 12.6 released yesterday/today does it again.
- Open ..\Music\iTunes\Previous iTunes Libraries
- Select the file iTunes Library 2016-09-26.itl and press Ctrl+C to copy it
- Navigate to ..\Music\iTunes and press Ctrl+V to paste
- Select the existing .itl file and press F2 to rename it, call it iTunes Library (Corrupt).itl
- Select and rename iTunes Library 2016-09-26.itl as iTunes Library.itl
- Open iTunes. You should see your library as it was last September.
For 4 & 5 if you don't see the .itl file extensions listed in Windows Explorer then the extension is hidden. Imagine it is there in both cases rather than adding it, otherwise you'll end up with a file ending in .itl.itl which iTunes won't try to open.
Let me know how you get on. Then we can talk about the other repairs or optimizations that might be worth carrying out. It isn't entirely clear to me yet if all of the media content located outside of ..\Music\iTunes\iTunes Music is duplicate or unwanted stuff that can be discarded, content that has never been added to the active library, but should have been, content that has been added, but in a way that left outside of the active media folder, or some combination of all three.
Regarding the specific questions you asked earlier:
5. Question - What should be the folder structure for iTunes on a Windows 10 PC?
The right-hand layout shown in Make a split library portable.
6. Question - After I get the correct folder structure how do I get iTunes to use it?
Better to get iTunes to make the changes once it is displaying your media, using some of the steps from the same user tip. I can guide you through which later.
7 .Question - Assuming that Music\iTunes\iTunes\AudioBooks is correct when I sync with the iPhone will the books contained in that folder then appear when I select Audiobooks on the iPhone? "AND" can I then play the book without issues?
The correct folder for audiobooks in a well-formed iTunes library is <Media Folder>\Audiobooks\<Author>, however iTunes should be able to sync any media that is designated as an audiobook (or other specific media type) to your devices provided it is selected to sync and it is wherever iTunes knows it to be located. iTunes is generally agnostic to the particular locations of files except when you try to move the library to a new path or computer, then it definitely helps to use the standard names for the library folder (iTunes), media folder (iTunes Media) and to have all content connected to the library inside the media folder.
tt2