A bug in Intel network card drivers distributed via Windows Update is causing IPv6 connectivity issues. The flaw affects the Intel Connectivity Performance Suite (ICPS), specifically the traffic control driver component IntcCo11X64.sys version 11.5.11.19. This issue prevents services like Microsoft 365, OneDrive, OneNote, Teams, and the Azure portal from functioning correctly by resetting the IPv6 Flow Label field to zero, which disrupts server routing.
The problem impacts devices from multiple manufacturers, including Samsung, Lenovo, VAIO, ASUS, HP, Dynabook, and Huaqin. Analysis of the Microsoft Update Catalog revealed 1086 ICPS entries from 19 companies, with only one version verified as fixed. Tests showed that while the faulty driver caused significant connection failures, disabling the INTCCoSvc driver or updating to the generic ICPS version 50.26.623.243 resolved the connectivity errors.
Despite reports dating back to November 2025, Intel, Microsoft, and Samsung have been slow to address the issue. Users report that support tickets have remained unresolved for weeks, and previous attempts to raise the issue on community forums were dismissed or marked as spam. While the latest generic driver from Intel appears to fix the behavior, the company has not explicitly mentioned an IPv6-related patch in its official release notes.
