I have 3 Dell laptops all with latest windows and all updates. For the past several weeks I have been having issues with computers not going to sleep. All relate to MoUsoCoreWorker.exe, as reported in Powercfg.Requests, as others have said.
Restarting the Windows Update procedure, as reported by others, would not clear the problem by itself. These additional steps did the trick for me:
- Power down the laptop.
- Remove all peripherals including docking stations etc.
- Unplug wall Power Adapter.
- REMOVE THE LAPTOP BATTERY.
- Press and hold the Computer Start button for a few seconds to bleed any residual power out.
- Reassemble the computer, and boot up normally.
- Rerun Windows Update. Computer may then reveal what is hanging up the system, and allow the update software installation to continue.
- When update is completed, Reboot normally, then run Powercfg /Requests. With luck you should then see there is no more MoUsoCoreWorker.exe flagged there.
Unfortunately you will probably have to do this again after the next Windows Update screwup happens. I wish Microsoft would fix this.