"After several failed boots [it does] a rollback and [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," wrote the reporter.
It's not clear how widespread this issue is, but the reporter noted that the CPU involved is "quite pre-historic", specifically the AMD Athlon X2 6000+, which was released a decade ago. Others who report the same issue are also using older AMD chips.
It's also not certain that Microsoft's patches for the Meltdown and Spectre attacks are the actual cause of the problems, given KB4056892 contains much more than these specific security fixes.
AMD said in a statement that the chipmaker "is aware of an issue with some older generation processors following installation of a Microsoft security update that was published over the weekend."
"AMD and Microsoft have been working on an update to resolve the issue and expect it to begin rolling out again for those impacted shortly," the statement added.
Microsoft hasn't responded specifically to the reports yet, instead issuing a general statement relating to the Meltdown and Spectre problem.
AMD chips aren't vulnerable to the Meltdown attack, but operating system updates could address one of the Spectre attacks it was vulnerable to.
AMD said there was a "near zero risk" its chips could be exploited by the second Spectre attack, which required firmware updates from OEMs containing CPU fixes such as Intel's IBRS microcode fix or Google's Retpoline software fix.
Most Intel processors and some ARM chips are confirmed to be vulnerable, putting billions of devices at risk of attacks. One of the security researchers said the bugs are "going to haunt us for years."
A serious security memory problem in all Intel chips has led to Linux's developers resetting how to deal with memory. The result will be a more secure, but -- as Linux creator Linus Torvalds says -- slower operating system.