What's causing iTunes to randomly display a 4002 error?

Once every day or two, iTunes seemingly randomly displays a 4002 error:

error screenshot

This is particularly puzzling to me, as the majority of the time (if not always) iTunes is in the background, and has been for a while. What exactly does the error signify, and how can I fix it?


Solution 1:

I got rid of this pesky error by

  1. turning iTunes Match off
  2. quit iTunes
  3. launch iTunes
  4. turn iTunes Match on

The first time iTunes complained with error 5002 during Match startup, but then it worked.