iTunes has got itself into a terrible muddle. It's been trying to update to a newer version (7.4.1 I assume) for ages now. Software update would pop up and say it had an update, would go away and download it and would then, once the download was completed, seemed to take another look and say that it didn't want to install anything after all. This has been occurring for over a month now I think.
This afternoon, when I opened iTunes it seemed to think it was running a new version and showed me the software agreement. I assumed that it had caught up with itself and didn't bother to think any more about it.
Now, when I open iTunes (I know I said I was going to bed, but I remembered a quick piece of code I could write) it says:
The file "iTunes Library" cannot be read because it was created by a newer version of iTunes.
So it seems that whatever it installed has gone away again. I had a look at version.plist and that says it's currently version 1.3.1 that's installed. As I now can't use iTunes at all I've decided to download a copy of 7.4.1 from the Apple site and hope it'll be all happy again...
On the plus side, my code change was a five minute job so I have achieved something by delaying my sleep some more.