Greyed out: "Upgrade to iTunes media organization"

Update: To make the "Upgrade to iTunes media organization" option clickable, I edited the .iTunes Preferences.plist hidden file, with the integer value 0.

When I start iTunes now, the option is no longer greyed out, however, when I select it and click OK. It doesn't show any progress or anything. All it does is change the integer value back to 1.

So I still have iTunes Media and iTunes Music folders, both with files inside.

Should I just manually merge the files from iTunes Music into iTunes Media?

If I do that manual merge via Finder:

- Some folders will overlap (e.g. Compilations, certain albums), so can I just merge all the files into one of these sub-folders via Finder?

- Should I leave iTunes on, or should I quit it?

- What other precautions should I take?

- How do I force iTunes to look through all the songs and see if they're all in the right places? I know if they're not, they'll get a ⚠ mark next to them... how can I make iTunes check without playing each file or whatever?

Sorry, when should I do this? After making the integer value back to 0?

iTunes prefs > Advanced.

Uncheck Keep iTunes media folder organized then click OK.

Then iTunes prefs > Advanced and tick Keep ITunes media folder organized.

Thanks, I did that, but to no avail. When I rechecked the box and hit OK, iTunes started working... but weirdly the blue indicator bar stared from about two-thirds in... and not from the start:

(Organizing Files)

It didn't take long to finish, but when it did — I took a look at the file structure of the folders, and nothing had been changed. Nothing seemed to be missing from iTunes Music, and no new additions were made to iTunes Media/Music...

What do you think the problem is?

Thanks. Just a last post before I do that:

1. Is that 100% safe? Everywhere I've read it advises against messing with stuff manually...

2. Wouldn't it be better to run the Consolidate Files command? Though that would make duplicates, and simply copy over everytihing in /iTunes Music/ to /iTunes Media/Music/... no?

3. And will it copy everything over 100%, thus being safe to delete the iTunes Music folder?

4. How would I check that it's worked and copied everything over? How do I force iTunes to look through all the songs and see if they're all in the right places? I know if they're not, they'll get a ⚠ mark next to them... how can I make iTunes check without playing each file or whatever?

5. So I should quit iTunes before doing this? Shouldn't I leave it on, so that it can track where files are moved... because if I quit, it'll close thinking everything is in the iTunes Music folder... and then open, finding it doesn't exist... will it know?

OK thanks! I will try and report back.