Jerry Dammers wrote:
I use Garage Band to mix playlists of, for example, 40 tracks.
My last track doesn't go as far as the end of the playlist, so I can't delete the end.
Not sure why the playlist continues for an extra 20 minutes after the end of the last track but I can't seem to delete it (but I could in a previous version of GarageBand).
There seems to be some major misunderstanding what about the concept of GarageBand. The Main Window does not represent a "Playlist". This is your Song or Project presented by the horizontal Timeline. That Timeline is as long as you record Regions on your Tracks. You could have a recorded Audio Region from bar 1 to bar 20, but your timeline could end at bar 100. It is like having a 100 page book where page 21 to 100 is blank.
So basically, you don't "delete the end", because there is nothing to delete. It doesn't matter when you bounce your mix, because you can restrict your bounce to the selected Region or the selected Cycle Range, instead of bounce the entire Song (with the empty bars)
If you want to get rid of the unused timeline area, you have to move the End Marker, that indicates the end of your Project to the left. The End Marker is that little triangle at the end of the Timeline Ruler. This is a little bit messed up, because that Marker is covered by the horizontal Zoom Slider. You have to aim with your mouse cursor a little bit above that slider and you will see the cursor change to the Trim Tool. Now click-drag to the left to move the End Marker.

Hope that helps
Edgar Rothermich - LogicProGEM.com
(Author of the "Graphically Enhanced Manuals")
http://DingDingMusic.com/Manuals/
'I may receive some form of compensation, financial or otherwise, from my recommendation or link.'