If you didn't purchase a license from cakewalk to unlock the mp3 encoder, it expires after 30 days. You need to purchase a license separately. Yes, we know most people think that its crazy to pay so much for a professional program and then have to pay for the mp3 encoder. Yes we know many people are indignant and think that its just wrong. Yes, what is Cakewalk thinking, other programs include it for free. And yes, you can use a third party encoder and incorporate it into the tools menu or use it standalone. Yes if you tried the search function in the forum you would find about 89.3 billion posts about this subject. If you did purchase a license and lost it, call or e-mail Cakewalk and they will help you out. If you didin't purchase a license, you can purchase one at the cakewalk store. But your best bet is to use a third party encoder and either put it in the Tools menu or export your projects as .wavs and convert outside Sonar. Good luck.