- Microsoft's Global Device Identifier (GDID) is a persistent, unique digital fingerprint assigned to Windows installations when users sign in with a Microsoft Account, used for licensing and tracking across services.
- The FBI used GDID to trace alleged hacker Peter Stokes by linking his Windows device's activity across VPNs and proxies to his online accounts, leading to his arrest at Helsinki airport in 2026.
- Privacy concerns arise because GDID is assigned without user consent, lacks visible controls like on Apple or Android, and can persist across reinstalls via Microsoft Account linkages, raising surveillance questions.
- To mitigate GDID tracking, users can switch to local accounts, disable optional diagnostics and advertising IDs, turn off cloud search, or use Linux with Tor for high-risk activities.