Q: attempting to copy to the disk failed. The disk could not be read from or written to", and "itunes could not copy to the ipod because the file could not be read or written" WTH?

See this page.  Work through each suggestion as necessary.

http://support.apple.com/kb/HT1207

B-rock

did you fix this problem? im having the same issue... Im using window 7 and itunes lastest version and i restored my iphone 4s millions of time and nothing work! when im in any random song it just freeze itunes and my computer gets crazy..... as soon as i unplugged it out from the usb the compu start working perfectly....

HELP ME OUT PLEASE!!!!

I would recommend posting your question over in the iPhone forums as there are many knowledgeable individuals over there who should be able to assist you.

https://discussions.apple.com/community/iphone

B-rock

I had this problem when I used brackets in the iPhone name, removing them resolved it for me

I had this issue and couldn't figure out what it was for the life of me. I am running windows 7 and the latest version of itunes. I tried multiple reinstalls of itunes and restores of the ipod. I finally got it fixed by following this guide.

http://support.apple.com/kb/TS1539

Apparently there was an issue with my .dll files. Hope this helps.

I ran into this issue with my iPhone 6. I ended up needing to clear out the lockdown folder to get the phone to backup to my MacBook Pro again.

Reset the Lockdown folder in iTunes - Apple Support

I can't speak for everyone, but HERE'S MY SOLUTION.

Try reinstalling iTunes to a different hard drive. The problem I had was that when I installed Windows 10, I installed iTunes to a different hard drive than all of my music. I'm not sure why, but this seemed to mess up iTunes ability to read my files. If you haven't done so already, try installing iTunes to the same hard drive as your music.

I hope this helps