I bought this MK850 keyboard combo because I couldn't get my old K520 and M510 to work.
They would just randomly become inactive.
I though the problem was that they just couldn't work with Windows 11.
So just today I went out and bought a new MK850 and after installing it I discovered they also would randomly become inactive.
After unsuccessfully trying numerous fixes, I was just about to call tech support when I thought I would try 1 more fix.
I installed a USB extension cable so I could plug the Unifying Receiver into it and locate the receiver as close as possible to the keyboard and mouse. So far, no more problem. PASS IT ON.