Microsoft is no longer signing Windows drivers for Process Hacker, a free and open-source tool for monitoring system resources and detecting malware. The developer of Process Hacker claims that Microsoft's actions are anti-competitive and aimed at eliminating competition. The issue is related to Microsoft's restrictions on the Windows API, which block third-party software from accessing certain features. This has sparked concerns about Microsoft's control over the Windows ecosystem and its impact on users' freedom to choose their software.