I am using Windows 11 on a legacy PC using UEFI boot. Avast error code 42125 has become evident when I run Avast boot scan, after the Windows June 2026 update. The update seems to be the cause of this. I am no expert and am baffled as to what to do about it. The system seems to work OK in regular use. I am worried that the next Patch Tuesday in July will not go well. The system worked great before running Windows update today.