Google by Alphabet Inc. (GOOGL  ) (GOOG  ) has lodged a complaint with the European Commission on Wednesday, alleging Microsoft Corp. (MSFT  ) of anti-competitive practices in its cloud services.

What Happened: Google claims Microsoft is leveraging its dominant Windows Server operating system to lock customers into its Azure cloud platform, Reuters reported on Wednesday. Amit Zavery, Google Cloud Vice President, stated that Microsoft imposes a 400% markup for customers running Windows Server on competing cloud services, which does not apply to Azure users.

According to Zavery, customers using rival cloud systems receive delayed and limited security updates. Google referenced a 2023 study by CISPE, indicating European businesses and public sector bodies incur up to 1 billion euros annually in Microsoft licensing penalties.

In July, Microsoft settled a 20-million-euro antitrust complaint with CISPE, avoiding an EU investigation. However, the settlement excluded Amazon Web Services (AMZN  ) and Google Cloud Platform, drawing criticism from both companies.

Microsoft responded, stating it had resolved similar concerns with European cloud providers and suggested Google would not succeed in persuading the European Commission. Google argues that regulatory action is necessary to end Microsoft's "vendor lock" and ensure a competitive cloud market.

Why It Matters: Google's complaint is the latest in a series of antitrust challenges against Microsoft's cloud practices. In December 2023, Google urged the U.K.'s Competition and Markets Authority (CMA) to investigate Microsoft for allegedly using licensing practices that discourage consumers from using other services, even as secondary providers to its Azure platform. This followed concerns raised by Ofcom about Microsoft and Amazon Inc. dominating the cloud computing industry.

Earlier in February, Microsoft was actively negotiating with the Cloud Infrastructure Services Providers in Europe (CISPE) to address a complaint lodged with the European Union. This move aimed to preempt a potential in-depth EU investigation, which could result in fines and a mandate for Microsoft to alter its business operations. CISPE, comprising Amazon and 26 smaller cloud providers across the EU, accused Microsoft of implementing contractual terms that detrimentally impact the European cloud computing environment.