One of the offered important updates via Windows Update, the Security Update for Microsoft Windows KB2419640 alledgedly had failed to install. The rest (5 others) installed fine.
But according to the list in Control Panel \ Programs and Features > Installed Updates, Security Update for Microsoft Windows KB2419640 was installed.
Only Windows Update keeps insisting the update had failed to install.
Solution:
Uninstall it from Programs and Features > Installed Updates
reboot PC
open Windows Update > redownload and install it.
on the prompt, reboot PC
and this time success.
Main PC: Asus TUF Gaming 570-Pro (wi-fi) * AMD Ryzen 7 5800X * Noctua NH-D15 * Corsair Vengeance LPX 32GB * Asus TUF Radeon 6800XT * Creative AE-9PE * 2 x Samsung 980 Pro * 7 x WD Gold HDD * Corsair HX 1000 * 1 x Asus DRW-24D5MT * Dell U3010 * Windows 10 x64 *
Office PC: Asus ROG Strix X570-E * AMD Ryzen 7 3800X * Noctua NH-D15 * Corsair Vengeance LPX 32GB * MSI Radeon 5700XT * Creative Soundblaster ZxR * 2 x Corsair Force MP600 * 7 x WD Gold HDD * Corsair AX 1200W * 1 x Asus DRW-24D5MT * Dell P4317Q * Windows 10 x64 *
Old workhorse PC: * Intel i7 4790K * Noctua NH-D15S * Asus Maximus VII Hero * Corsair Force MP510 480GB M.2 SSD * 32 GB Corsair Dominator Platinum CMD32GX3M4A2133C9 * Sapphire Radeon R9 290 * 3 x Dell U2410 @ Eyefinity 5760 x 1200 * Corsair HX 1000i * 7 x WD Black / Gold HDDs * Creative Soundblaster ZxR * Asus DRW F1ST * Corsair K95 RGB * Corsair M65 PRO RGB * Steelseries 9HD * Coolermaster STC T01 * Edifier S530 * Sennheiser HD598 * Windows 10 x64 *
