Over the last few weeks, Intel, Microsoft and other firms have been working double-time to push out fixes for the Spectre bug following its public unveiling. The bug poses as a serious security concern, so there is plenty of need for swift action. However, that has come at the expense of several errors along the way. One of Intel's own Spectre fixes turned out to contain a bug that could lead to data corruption. This is being fixed but in the meantime, Microsoft has pushed out its own Windows patch that disables Intel's prior buggy fix.
Intel did warn people away from the patch last week until a more stable patch can be released. In the interim, Microsoft has issued its own patch to disable the fix, which targets the second variant of the Spectre bug, which allows for ‘Branch Target Injection’.
The Microsoft patch is available for Windows 10, Windows 8.1 and Windows 7, so if you installed the previous Intel fix and encountered errors, this Windows patch should fix that. Your system will remain protected against Spectre variant 1. Variant 2 requires physical access to a machine to exploit, so your system shouldn't be at too much risk while a bug-free patch is developed.
KitGuru Says: If you installed Intel's Spectre 2 patch, then you should update Windows in order to avoid any unexpected errors. In the meantime, I imagine Intel will be pushing out an updated version of its patch later this week. Hopefully the next one will be free of issues.