Microsoft is engaged in a legal dispute with ValueLicensing, a UK reseller of pre-owned software licenses, which is being heard at the Competition Appeal Tribunal. Microsoft claims that the resale of these licenses is unlawful, arguing it holds copyright over not just the software code but also components like the graphical user interface. ValueLicensing alleges that Microsoft has restricted the resale market by incentivizing customers to switch to subscription services and including clauses in contracts that limit resale rights, resulting in an estimated £270 million in lost profits. The case could significantly impact the future of the second-hand software marketplace in Europe.