Court of Justice rules that software buyers can decompile programs to correct errors

October 14, 2021

The Court of Justice of the European Union has issued its ruling in the case of Top System SA v Belgian State (Case C-13/20). It considered the exceptions to the restricted acts under Article 5(1) of the Software Directive (91/250/EEC) and ruled that a buyer of a computer program was entitled to decompile it to correct errors. 

Although the 1991 Directive has been replaced by the current Software Directive (Directive 2009/24/EC), the relevant provisions are substantively identical:

  • Articles 4(a) and (b) of the Directive provide that the right-holder in a computer program has the exclusive right to reproduce and alter the program. 
  • Article 5(1) says that in the absence of specific contractual provisions, the acts referred to in Article 4 (a) and (b) do not require authorisation by the rightsholder if they are necessary for the use of the computer program by the lawful acquirer in accordance with its intended purpose, including for error correction.
  • According to Article 6, the authorisation of the rightsholder shall not be required where reproduction of the code and translation of its form under Articles 4 (a) and (b) are indispensable to obtain the information necessary to achieve the interoperability of an independently created computer program with other programs, provided that the following conditions are met. The conditions are that those acts are performed by the licensee (or other authorised person), the information necessary to achieve interoperability was not already made available to the licensee and the acts were confined to the parts of the original program that were necessary to achieve interoperability. In addition, information gained by the decompilation must not be used for goals other than achieving interoperability, and any use of the decompilation should not unreasonably prejudice the right-holder’s legitimate interests or conflict with a normal exploitation of the software.

In this case, Top System developed software and licensed it to Selor, the staff selection agency of the Belgian government. A dispute arose between the parties about errors in the software. Selor decided to decompile the software to correct the errors without involving Top System. Top System started proceedings against Selor, claiming damages for the decompilation of its computer program without its authorisation. The Belgian courts referred the following questions to the CJEU:

  • Is Article 5(1) to be interpreted as permitting the lawful purchaser of a computer program to decompile all or part of that program where such decompilation is necessary to enable that person to correct errors affecting the operation of the program, including where the correction consists in disabling a function that is affecting the proper operation of the application of which the program forms a part?
  • If that question is answered in the affirmative, must the conditions referred to in Article 6 of the directive, or any other conditions, also be satisfied?

The court’s ruling

The court said that decompilation falls under “reproduction or adaptation” as set out in Articles 4(a) and (b) of the 1991 Software Directive. It further ruled that the lawful purchaser of a computer program is entitled to decompile all or part of that program to correct errors affecting its operation, including where the correction consists in disabling a function that is affecting the proper operation of the application of which that program forms a part.

Although the court said that the conditions in Article 6 did not have to be satisfied, they did say that a purchaser is entitled to carry out such a decompilation only to the extent necessary to effect that correction and in compliance, where appropriate, with any conditions set out in the contract with the holder of the copyright in that program.