It happens quite a lot, that a license is not registered in the relevant patent register. In that case, the licensee cannot start any action against an infringer and cannot claim any damages. For that reason:
When writing the license agreement, it is sensible to put in who (licensee or licensor) is responsible for the registration, and what happens if this has not been done. The party most benefitting from a proper registration is the licensee, so he/she is the most likely party to have the responsibility of arranging a proper registration.
Hendrik de Lange
Dutch and European patent attorney
+31 (0) 648 174 686