Windows 10 updates follow each other and look the same at one point: sometimes they fix almost as many bugs as they bring. The latter can thus cause the impossibility of placing the PC in standby.
The optional September update rolled out on Windows 10 has a few issues, one of which is a bug in the sleep system.
For a large number of users, the update thus purely blocks standby, a situation which is particularly problematic on laptops configured to go to standby when the cover is closed … Key: A PC that keeps running can be damaged if it is tossed around in a bag while it is running or simply end up draining its battery for nothing.
This is the MoUSO Core Worker process Process related to Windows Update which poses problem … And it is not recent since identical problems had already been pointed out in May … Microsoft had deployed a specific fix e.
While waiting for Microsoft to correct the situation again, one procedure is to stop the Windows Update process in Services.msc, then restart it before letting it perform all the updates.