Meltdown and Spectre are two recently-discovered data security flaws that affect older processors. Microsoft issued emergency fixes and patches to prevent malicious parties from taking advantage of the exploits. However, the fixes seemed to have brought some older PCs into an unbootable state.

Numerous complaints about older PCs not booting after installing the fixes were recently posted on the Microsoft community forums. The problem only seems to occur on PCs run by older AMD chipsets.

Microsoft's statement about the matter says that the problem is not with the fix, but with AMD's documentation.

In the statement, Microsoft said that "some AMD chipsets do not conform to the documentation previously provided to Microsoft to develop the Windows operating system mitigations to protect against the chipset vulnerabilities known as Spectre and Meltdown."

In essence, Microsoft is stating that they have rolled out the fixes, with the confidence that it will work on older AMD chipsets. This is based on the documentation the latter company provided.

AMD itself acknowledged the issue and said that they are "aware of an issue with some older generation processors." They also implied that the unbootable state was triggered by Microsoft Meltdown and Spectre fixes that were released last weekend.

Now that the issue has come to light, Microsoft has temporarily stopped automatically delivering updates to AMD computers. The two companies are said to be working together in order to create a fix that will work on affected machines.

Meanwhile, affected users are advised to visit Microsoft support site so that they can get their computer back to a bootable, operational state.

Meltdown and Spectre caught media attention when researchers discovered that the exploits affect all processors made in the last twenty years. Meltdown is the easiest to exploit of the two and is reportedly easier to fix.