Last week Microsoft released the KB4056892 security patch which addresses critical Meltdown and Spectre vulnerabilities on computers with Intel, AMD and ARM chipsets in Windows 10 operating system. However, it appears that the KB4056892 patch fails to install with 0x800f0845 critical error on PCs with AMD Athlon chipsets, leaving AMD-powered computers with the Windows startup logo and no further boot.
“I have older AMD Athlon 64 X2 6000+, Asus MB, after installation of KB4056892 the system doesn’t boot, it only shows the Windows logo without animation and nothing more. After several failed boots it do roll-back then it shows error 0x800f0845. Unfortunately, it seems it’s not easy to disable the automatic updates without gpedit tweaks, so it tries installing and rolling-back the update over and over. The sfc /scannow shows no problem, in-place upgrade also doesn’t seem to help. I can try full reinstall, but I doubt it will change anything. It seems like the update is binary incompatible with my old CPU. I understand that making the machine unbootable is the best protection from remote exploitation, but I would rather have the OS working. Especially if my CPU is not vulnerable to the Meltdown attack and the MS mitigation attempts for Spectre is more than questionable. I could find only some German and Italian people reporting the same issue (well the CPU is quite pre-historic and the KB update is very fresh), but no info / acknowledgment from the MS so far,” reported user named Jaroslav Skarvada on Microsoft’s community forum.
At the moment our experts aren’t aware of any fix for error 0x800f0845 while installing Windows 10 KB4056892 security patch. The bug is affecting some old AMD systems only. The patch doesn’t create a recovery point, so rollback is not accessible. Some users report that even re-installing Windows 10 doesn’t help matters. Meanwhile, others were able to recover their computers by quickly downloading and reinstalling the KB4056892 patch all over again.