Approximately 17% of all Windows client devices are still running Windows 10, equating to about one in six machines. Windows 11 accounts for 78% of Windows devices, with third-party trackers indicating it surpassed 70% of desktop share as of February 2026. Official support for Windows 10 ended in October 2025, but Microsoft’s Extended Security Updates (ESU) program will provide patches until October 2027 for eligible devices. A typical Windows 10 device has an average of 1,903 active security vulnerabilities, nearly three times the 652 CVE-tracked flaws found on a Windows 11 machine. 66% of Windows 10 vulnerabilities are classified as "high" or "critical." Small and medium enterprises have 21.4% of their Windows devices still on Windows 10, while larger enterprises have 16.6%. The healthcare and pharmaceuticals sectors have 23% of devices on Windows 10, followed by consumer and retail at 22%, and manufacturing at 18%. Lansweeper is urging organizations to enroll in the ESU program and address reasons for remaining on Windows 10 as 2026 approaches.