Can't record guitar using mono track only stereo track

When I try to record my guitar through an M-track Solo audio interface I cannot get any sound when I use a mono track. When I switch to stereo track the sound comes through on one side of the stereo track. Any ideas why I can’t record a mono track for my guitar?

I’m a Windows guy but I’d guess when you record in mono you’re only getting the (unused) microphone input.

There may be a MacOS setting to change that.

…But you can Split Stereo To Mono and then click the “x” to kill the silent track.