The sixth chapter of publication "Current Issues in Copyright Law and Industrial Law" analysis the judgment of the Court of Justice of the European Union C 13/20 Top System SA v Belgian state of 6 October 2021. The Court has decided in these proceedings on preliminary questions relating to the interpretation of Article 5(1) of Council Directive 91/250/EEC of 14 May 1991 on the legal protection of computer programs, in particular about the possibility for a lawful purchaser of a computer program to decompile the program in whole or in part in order to correct errors affecting the operation of that program.