Late answer but had this same problem with my Dell all week. Got a brand new ultra wide monitor and wanted my laptop shut to work like a desktop.Seems to be an issue with a lot of people on different computer models with no clear cut answer. Crazy frustrating but here’s what finally worked for me:
- Boot to Bios via F2 - Goto "usb for wake settings" set to enabled
- Device Mgr as admin, both keyboard and mouse properties have power settings with wake set to Enabled (you won't see power settings tab unless your admin)
- Control panel under power options, choose what to do "when lid closed", laptop plugged in set to "do nothing"
- Device Mgr as admin,HID properties, HID compliant devices power mgmt setting to enable wake Enabled
- Device Mgr try updating drivers of both keyboard and mouse if available/out of date
- If your wireless mouse keyboard is plugged to a USB hub (or 2nd Hub connected to 1st) with a ton of connected devices it may draw to much power which weakens the signal necessary when computer is in sleep mode. Unplug or deactivate/shut those other usb devices off. I have a Sabrenet usb3.0 from Amazon and it seems to have some power distribution issues when too many usb devices are active. I found this out by troubleshooting my USB ports. Honestly this was a major/silly find for me, but think this is what sealed the deal.
Device manager location and run as admin:
Can Try if still not working but weren't necessary:
- Control panel, Power options , go to your power plan settings, advanced settings go to usb settings select disable on both battery/plugged in
- Control panel, Power options , go to your power plan settings advanced settings go to sleep,allow wake timers on both battery/plugged in enabled