I've definitely had issues doing an upgrade on a real Ubuntu installation. Years ago I needed to update a more or less clean install of Ubuntu Desktop. It managed to completely break Gnome somehow (This was before Unity). I'm guessing things are better now and that the server distribution is better for this but I could see complications happening.

I used Ubuntu Server LTS a couple of times.

The 14.04 version which is supported until 2019 still has the bug that it won't clear out old kernels after upgrading them. So if you don't look into your /boot partition now and then it fills up and breaks your installation.

Can you link to a bug report? dist-upgrade (as opposed to upgrade) should remove the old packages;that's its whole point...

Xe could hyperlink you to Dustin Kirkland's call for feedback here on Hacker News only a short while ago, where this subject came up several times. This is a well-known Ubuntu problem, and M. Kirkland xyrself said that taking purge-old-kernels out of the byobu package and putting it somewhere more obvious was a good idea.

* https://news.ycombinator.com/item?id=14002821

Of course, this is an Ubuntu upgrade problem relating to Linux. It is specifically about kernel image files. So it has very little application to the Windows NT Linux Subsystem, which as we know uses the Windows NT kernel.

I'm sure you know but apt-get autoremove

After a major change of desktop like a switch from gnome 2 to unity or gnome 3, it is not surprising that users may need to refresh their configuration files. I am doing dist-upgrade since 2009. They were all smooth except the upgrade to 16.04 (lost of network and a couple of small issues still not fixed).

After 15 years with Ubuntu, I've only ever seen problems when people switched default Ubuntu packages with their own (back in the day it was often beryl, compiz or drivers).

I've had this problem many times in the past too. Including subsequent problems with dpkg after the upgrade to 16.04

Unless you are using a functional system like NixOS or Guix, upgrading can leave a mess of old installed files, and can be unpredictable.

If you're asking why Microsoft's advice is to format and reinstall, well, consider who it's coming from.

I don't know about Canonical, but Red Hat at least recommend reinstalling over in-place upgrades too.

Because you can upgrade from windows 3.11 all the way to 10, good luck with ubuntu.

Yeah, I see your point.

I have actual machines that I was able to flawlessly upgrade from 4.10 to 17.04. Can't say that about Windows. Though I did actually know what I shouldn't mess with if I want the upgrade to go through (or fix before).

You got extremely lucky. Not that windows is much better, but in general there are hiccups to upgrading with most linux distros as well as windows.

I hit problems with the desktop environment on both 8->10 and 10->12, then gave up trying to upgrade Ubuntu in-place. Debian has been absolutely fine, though.

> Because you can upgrade from windows 3.11 all the way to 10

That has never ever worked for me until the 7 -> 10 upgrade: 95 -> 98, 98 -> 2k, 2k -> XP and XP -> 7 all failed miserably and required installing from scratch.

And even 7 -> 10 failed without any helpful information= the first few times I tried it (unlike OSX where I've been upgrading and migrating the same system for more than 10 years across multiple machines and versions).

This is more like 7 -> 10 (14.04 is LTS predecessor to 16.04). Totally valid upgrade path.

There are people who have done it all of the way from Windows 1.