Backup copies of software are made routinely, and the sale of software no longer used is also commonplace, despite the fact that in many cases the software licence is not legally transferable.
However, what would the position be if the original purchaser decided to sell software that it no longer wished to use but the only available copy of it was a backup copy he had made?
The answer, according to the European Court of Justice, is that the backup cannot be legally sold without the permission of the owner of the copyright to the software, even if it is the only copy the purchaser has.