Your iPod/iPhone library can be corrupt for two reasons:

• The iPod was unplugged without having been properly ejected first
• The use of an alternative iPod manager

Please go through this troubleshooter to resolve the problem.

Solution A: Only for CopyTrans Manager users

• Restore the last iPod library backup (created automatically by CopyTrans Manager) by following this guide.
  If the last library does not fix the problem, try the previous one.

If Solution A does not help, don't forget to restore the iPod library with today’s date through CopyTrans Manager.

Solution B:

• Manually add a song to your iPod through iTunes.
• Close iTunes and open CopyTrans Manager again to check if the problem is fixed.
  WARNING: To avoid "Automatic synchronization” of your iPod by iTunes click and keep the Shift and Ctrl keys pressed while you open iTunes. Please refer to this FAQ article.

Solution C:

• Restore your iPod library through iTunes. This solution will always work but is radical.
  WARNING: This will completely erase the contents of your iPod. You should create a backup with CopyTrans before you restore.