Unable to manually add songs in iTunes 12

Hi,

I've been having some serious problems with itunes ever since it was updated to version 12 (I think - it was when the logo changed to pink).

Since then, I've been unable to add any songs the way I normally would.

As a bit of background, I've had ipods and/or iphones since around 2004 and in that time I have never had any of them set to sync automatically.

I've never had a problem manually adding songs in previous versions of itunes. However, since I updated my ipod to IOS 7 and it forced me to update itunes, it has completely wiped all of my songs from my device 5 times, despite the fact that I have automatic syncing disabled and it is set to warn me if more than 5% of my data will be changed. It has got to the stage where I've just stopped connecting my ipod to my laptop and basically stopped using it altogether.

I also have a 120GB iphone 6 (currently iOS 8.1.2), which also has automatic syncing disabled. This was also wiped once, but the main problem is when I try to manually add individual songs to the iphone. Occasionally it works, but usually it just shows up greyed out and gets stuck on "preparing to sync". At one point I left it connected overnight trying to add one song, so it's not a timing issue.

I should mention, on the occasions when my devices were wiped, the songs were available in itunes, so it wasn't a case that my local PC library was empty.

Not that it should have synced anyway.

Has anyone else had a similar problem, or does anyone know what I could try to fix it?

Thanks,

Johnny