Almost a quarter of users are still running a Windows OS without mainstream support: Survey May 03, 2021 24% of users are still running a Windows OS without mainstream support Almost a quarter of users are still running a Windows operating system (OS) without mainstream support, according to a study by cybersecurity firm Kaspersky. Kaspersky conducted a study based on anonymized OS metadata provided by consenting Kaspersky Security Network users. According to the survey, 22 per cent of PC users are still using the end-of-life OS Windows 7. Official support for Microsoft Windows 7 ended in January 2020. When an OS comes to the end of its lifecycle, the vendor stops providing updates for the OS including critical security fixes.