I have this same problem. Tried the solution of de-authorising all computers. However, when I try to re-authorise the computer, I get the same (-42048) error, with a message saying there was an error in the iTunes store. So this isn't recommended.
Currently Being ModeratedNov 30, 2012 1:58 AM (in response to unicorn27)
when I try to re-authorise the computer, I get the same (-42048) error
Thanks for the input, unicorn27! This suggests that whatever iTunes does to identify itself to the Store is the issue.
If anyone has any insight as to what files are involved in this process, that would be great!
Currently Being ModeratedDec 3, 2012 10:32 PM (in response to rootbeerinacan)
I cannot exactly tell you what fixes the problem but it seems that when you just install iTunes 10.7 again it does not overwrite all files which have been altered by the iTunes 11 installation. But following this short tutorial fixed the -42048 error for me:
All kudos go to the original post author bogoss. Hope it helps.