Unlike standard downloadable content (DLC), disc-based music games operate under strict, time-limited licensing agreements with record labels and music publishers. Harmonix secured the rights to distribute these songs on physical discs and offer digital export windows, but those windows had hard expiration dates.
However, in December 2020, Harmonix officially retired the Rock Band 3 export key due to expiring licenses, marking the end of the major disc-export era. How to Expand Your Rock Band 4 Library Today rock band song export key
The original game allowed players to export 55 of its 58 on-disc tracks into Rock Band 2 and subsequent titles. Three songs (including tracks by Metallica and Iron Maiden) were excluded due to licensing restrictions. Rock Band 2 (2008) How to Expand Your Rock Band 4 Library
: These have long since expired. If you did not purchase the export key while it was active (circa 2010–2015), you can no longer export these full soundtracks. Rock Band 3 Export If you did not purchase the export key
Once a licensing agreement lapsed, Harmonix lost the legal right to sell the Export Key. Consequently, almost all official Rock Band disc exports have been discontinued. Here is the expiration status for the major titles: