Microsoft rolled out KB4515384, a new cumulative update for Windows 10 version 1903. This update contains a patch for the Cortana search issue, which caused a spike in CPU load (and thus also power consumption) on some systems.
Additionally, the patch also has some security updates, including patches for two zero-day bugs that allow elevation of privilege. There are also updates that offer protection against microarchitecture data sampling (MDS) another speculative execution side-channel vulnerability, but this only affects 32-bit users of Windows 10.
But its fix has nixed SearchUI.exe for some. Those griping claim SearchUI.exe, a part of Cortana, won't launch after installing KB4515384.
"What a mess – I had the original issue with SearchUI.exe and it sending my CPU to unparalleled heights and showing a big black pane of nothing," wrote Reddit user cyrenaic101 in a complaint thread. "So I uninstalled that turd. And then here comes the 'fix' KB4515384. Search completely broken…"
Similar complaints surfaced in another Reddit discussion of the updates.
We suppose Microsoft will need to do more beta testing on users to ensure they get to the bottom of this.