Right-clicking the track and selecting Clean Up Lanes doesn’t remove Lane 4 in the pictured situation in Cubase 10 Pro version 10.0.20 Build 187 on macOS version 10.14.5.
I found it’s because you have to delete all the parts you don’t want , then it will work, but the easier way I found is to simply bounce the track down, that command is in the Audio menu at the top.
I am not a very experienced user so there might be better answers, this is just what I have found works.
Hope it helps
Yeah, thanks. I just think it’s weird that it doesn’t remove the empty lane.
It always spare a record-ready lane