I was having very slow startup after the GUI was established. The UM System monitor told me it was doing something ‘big’ with the CPU but it was not showing much disc activity. The processes seemed to be mainly ‘await’ with very little else, ie the cores were not busy. It took me about a month to figure this out, as a result I am not feeling as confident as I was. ie overwhelmed by feelings of Newby-ness.
All it took to cure the problem was to empty the Rubbish Bin. For some reason UM is obsessed with peering into the Rubbish Bin for about 3-4minutes if you have it chocker block like I did. I had recently installed a clean UM system and liking it very much, but I carried over a couple of legacy folders from previous disks, then sorted through them and deleted old stuff, duplicates etc
Probably a widely known fact, but as the Coasters sang “Take out that paper and the Trash, or you don’t get no spendin’ cash” 
Interesting. That issue I never had.
But powering down times vary quite a bit for me.
Hi @robwlakes,
as interesting as your suggestion is; I use “Bleachbit” on an almost daily basis and still have slow start and shutdown speeds on UM, maybe a bug?. 
Hi Wolfman, Sorry I can’t be more help. All I know and can report is I
had this huge wait time 3-4mins before my system became “usable”, ie
before mouse clicks actually worked. I inspected the System Monitor for
weeks trying to figure it out. As soon as the Rubbish was emptied it was
reduced to a minor blip, 3-4seconds, after the GUI appears. My
understanding of Linux in general is not sophisticated enough to suggest
alternatives. I felt I was responsible for “abusing” the Rubbish system
My shutdown has always been fast. Rob
Thanks @robwlakes,
it’s not a biggy as I can survive the couple of extra minutes!. 