Windows 10 refuses to die, and the security bill is coming due

A hard core of Windows 10 devices cannot or will not be migrated to Windows 11, leaving enterprises with a growing security problem as support options run out. According to asset tracking service Lansweeper, Windows 10 still runs on 16.9 percent of the Windows devices it monitors, or "roughly one in six." A year ago, the operating system accounted for about half of the machines in its dataset, falling to the low-to-mid 40 percent range by the time Microsoft ended standard support. The decline continued after that, reaching 18.6 percent in June, but Lansweeper says migration has now slowed to a crawl. This presents a problem because even installations enrolled in the Extended Security Updates (ESU) program, under which Microsoft has committed to fixing security bugs, will eventually become vulnerable. Consumer devices can receive security updates until October 12, 2027, while commercial customers willing to pay can extend coverage until October 10, 2028. After that, the fixes stop. Small and medium-sized businesses (SMBs) are particularly exposed. Lansweeper reckons that 21.4 percent of SMB machines still run Windows 10, with cost usually being the constraint that keeps the legacy operating system running. The exposure is greater in some sectors, with 23 percent of healthcare and pharmaceutical systems sticking with Windows 10, while consumer and retail devices hover at 22.7 percent. According to Lansweeper's data, "a Windows 10 device carries an average of 1,903 active CVEs against 652 on Windows 11. That's a 2.9x gap." Esben Dochy, principal technical evangelist at the company, told The Register that "the Windows 10 average also includes devices that have ESU patches applied." Part of the problem, according to Lansweeper, is "patch diffing," in which Windows 11 fixes can be reverse-engineered to find flaws in Windows 10. "The supported OS effectively hands attackers a map into the unsupported one," Lansweeper said. According to Lansweeper's figures, 14 percent of W