A Spanish open software group has filed a complaint with the European Commission accusing Microsoft of unfairly locking out other operating systems.
Hispalinux is said to be targeting Redmond's use of the UEFI Secure Boot component unfairly prevents users from installing third-party software.
Designed as a security component, the UEFI specification creates a platform which verifies critical system components before booting up a system, hopefully preventing malware infections from altering vital components.
According to a report from Reuters, the Hispalinux filing argues that Microsoft's means of implementing UEFI require third-parties to obtain permissions from the company before installing additional operating systems, potentially allowing the company to control or eliminate competition.
Microsoft, meanwhile, is maintaining that its use of UEFI is nothing more than a move to improve system security and would not harm competition.
"UEFI is an industry standard aimed at improving computer security and the approach has been public for some time," the company said in a statement provided to V3.
"We're happy to answer any additional questions but we are confident our approach complies with the law and helps keep customers safe."
Redmond has previously listed the UEFI framework as one of the key components to its security strategy.
At this year's RSA conference, Microsoft vice president of Trustworthy Computing, Scott Charney said that the platform would help to improve performance by giving users a trusted boot cycle which can prevent sophisticated malware infections from sneaking under the radar.