Users discovered this is the fault of a Windows Update process called “MoUSO Core Worker Process.” It’s causing unwanted wakeups on PCs that have applied Windows 10 version 2004 and have an optional update pending for installation. Sleep Mode: annoying when it doesn't work “When I close the lid, press the power button, or select Sleep in the power menu or the win-x menu, instead of sleeping, the screen simply turns off, and my laptop does not go to sleep even after leaving it alone all night,” one person wrote on Microsoft’s forum. Windows 10 KB4568831 fixed the borked Sleep Mode, but the problem has returned for some users who’ve installed the September 2020 optional update. Windows Latest reports that the issue first appeared with the Windows May 2020 update, which introduced a slew of glitches to many PCs.

On this occasion, the bug is affecting some machines' Sleep Mode, with cases of computers repeatedly waking up for no reason, or the low power state not working at all.

Facepalm: In a totally unexpected turn of events, a Windows 10 update has broken one of the OS’s major features.

Windows 10 update sleep