Windows decides your networking software isn't properly credentialed, cuts its connections

July’s Patch Tuesday tightened validation on Transport Driver Interface providers: the I/O manager now filters out sockets whose transport driver isn’t correctly registered with Windows, and applications relying on unregistered third-party TDI providers simply stop being able to open network connections. Consumer software mostly shrugged this off; the casualties are the software nobody wants to touch — aging security agents, VPN clients, network utilities, industrial control applications, and proprietary protocol stacks that have ridden through a decade of in-place upgrades. Microsoft documented the change as a compatibility note rather than a bug, and the fix is to get the vendor to ship a properly registered driver. There is a registry mitigation that lowers the validation level, which Microsoft accompanies with the observation that this lowers your security, which it does. The same update did at least resolve June’s Recycle Bin dialog bug and the OneDrive shortcuts breaking under an elevated File Explorer.