Win11 losing keyboard/mouse shortly after starting

Previous post, Upgrade from Win10 to Win11 23h2 using Rufus on unsupported hardware re: installing on unsupported hardware (so, could be the cause, but...)
Installed (23H2) and apparently working fine, except:
a while after logging in (and I think generally after a short period of inactivity), keyboard/mouse (both inbuilt and using a usb dongle) stop responding to any input. Have found that ny putting into sleep mode and waking, all comes good for another period of time, but will happen again, down the road.
Seem to have a lot of: Event 48, BTHUSB - "The local adaptor does not support the encryption key size for a connected device."

Any ideas?

Dell Precision M4300 (I know...)

Open Device Manager > Bluetooth and right click on the various entries there and select Properties. You want to go to the Power Management tab, if it exists and then disable Allow the computer to turn off this device to save power.

Do the same with Universal Serial Bus controllers.



With a little luck that should help.

While you are there, it would not hurt to update the drivers. Also visit the Dell website and download any updated USB/Bluetooth drivers and install them.