Keyboard input stops

[GegH1]

Periodically, without reason, my keyboard input stops working.

I type commands and nothing appears in the command line. I've seen posts saying that it might be the "PICKFIRST" option but this is not the case.

I either have to close Autocad and restart, or i can open Options, not change anything, then close options and the command line starts working again.

When you look closely whilst typing on the command line you see the cursor moving along the line, but no letters appearing as if they are white letters on a white background...but on hitting enter no command has been registered.

This is the same for Autocad 2021 or Autocad Civil 3d 2021

[S.Faris]

This is a last resort method.(Try this method, only if you fully understand what you are going to do) Always choose to backup

How to reset AutoCAD to defaults 

Typing a command in the command line, and it does not show up in Civil 3D 2015 or 2016 

[pendean]

Sadly there is no fix for random: what else an you share that sheds light on the trigger. Could be you've been in the same file for 4-6-8hours? Or first thing in the morning? Or this is a remote access situation? Or..?
There is no fix for random-triggered problems sadly.

wireless keyboard? try a wired one for a while.
Video card choking (fix is to restart the program)? Turn off hardware acceleration and see if that helps.

[Erense]

It might also be related to the commandline being 'docked' or 'floating', mostly this is also a graphics issue.