When I have subscribe to iTunes Match and access my music library with 6000 songs, I get the error 4001 on my Mac as well as on my PC. I have been completely unsuccessful getting it to sync. The same problem after 48 hours.
The most common errors with iMatch are “4001” and “4002”. Here is the solution to fix the problem. Works for a lot of users.
* Open iTunes > click the Store tab.
* Hold down the Option Key on the keyboard and click “Turn Off iTunes Match” at the same time.
* From the menu, click “Store” > “Turn on iTunes Match”. If you have lots of songs, it will takes you a long time.