Manual says that all extra voices will disappear on project close if they are not being used. Well, I’ve closed Dorico and reopened it, and the extra voices are still there and visible in the playback mixer.
I’ve tried selecting-all and then Filter for whatever voice “Down-Stem 7”, but nothing happens. Everything remains selected and hitting delete kills everything.
See attached.
Freight Train - More.dorico (1.2 MB)
I’m not at my machine but have you tried turning on Voice Colors? This will tell you for certain if there are other voices anywhere.
Also, what do you mean by
?
(Voice Colors! Where were you 3 hours ago! 
I was wondering why tf Dorico didn’t have that…)
I mean, in the “Play” tab -
Do you have Independent Voice Playback enabled? If so, try disabling:
I would expect reapplying the playback template to solve this also.
I’m not even sure what a Playback Template is - Where/How do you “reapply” it?
In the Play menu > Playback Template …
Just hit the Apply and Close button and wait a few seconds for everything to reconfigure. The “power” button in the toolbar goes off and back on.
A Playback Template sets up all the VSTs, loads all the patches and assigns all the Expression Maps to the instruments present in the score.
Dorico has a number of factory templates, or you can create your own templates to suit particular sound libraries you want to use.
You can set a preference so that new scores will start with a playback template of your choice.
