With my recent embracing of Linux for my desktop PC, and my tendency to want to install various software that’s not necessarily ready for primetime, it was inevitable that I would run into the dreaded “dependencies hell” situation where something gets broken and ends up breaking other things. Well, I’m still typing this on my now-fixed Linux desktop, so this is definitely not one of these “screw Linux, I’m going back to Windows” post, and I’ll walk everyone through this incident in detail so that if by some chance you find yourself having a problem such as this, you will not panic and be able to repair things.
So yesterday I was going through some of my old archives and saw a big fonts package. We’re talking 1000+ fonts. I don’t want to install all of those, but I wanted to have a fonts manager app so I can have a visual preview of all of them and enable/disable some of them without wanting to move files around directly. One of the apps I saw listed as available for Linux was fontbase, and from the web site I thought it looked really interesting. It is distributed as an appImage, which I don’t like — we Linux users have to deal with multiple software packaging methods already — but it’s supposed to be a way software can be installed without requiring a separate app (like apt, flatpak, etc.) so I gave it a try.
Usually the way to install an appImage file is to make it executable and double-click it, so I do that… and nothing happens. I bring it up in Nautilus (“Files”), right-click and select run, and again, nothing. So I grumble and open a terminal from my Downloads folder and run it (with ./[file]), and get an error message:
dlopen(): error loading libfuse.so.2
AppImages require FUSE to run.
You might still be able to extract the contents of this AppImage
if you run it with the –appimage-extract option.
This error occurs because Ubuntu switched from FUSE2 to FUSE3. A long time ago. However I did not know that, and foolishly did not research this ahead of time. So I assumed that FUSE was not installed at all, and that’s how this all started.
Naturally I went to a terminal and entered “apt install fuse”. Apt warned me it would have to install a lot of packages and, more importantly, remove a lot of packages. However I was in the middle of playing a game and was not paying sufficient attention. If I had been paying attention I would have noticed that the packages to be removed included things like “ubuntu-desktop”, which is pretty important on a working Ubuntu desktop system!
Unfortunately I just hit enter to start the process. This did not have any impact on running applications so I kept doing what I was doing, playing the game (it was “Car Mechanic Simulator” on Steam, if you’re curious), and then I watched the Japanese Grand Prix, and went to bed.
When I woke up is when I realized how badly I had screwed this up. I woke my computer from sleep, but I couldn’t enter my password. So, I reluctantly did a hard reboot on the system — hold down the power key for 5+ seconds, then restart — and that’s when I became aware that I had made a huge mistake.
So the computer restarts, I get the initial Ubuntu screen… and then it disappears and shows me the console output of the system startup. That’s not a good sign. Also the last message I saw was that gdm had failed. That’s really great, I thought sarcastically. And that’s when it hit me that installing the “fuse” package was the origin of the problem. I looked up whether the apt system has a rollback system, and it does not — maybe that’s why Ubuntu now uses snap. However it gave me a starting point. Fortunately I still had my phone working so I looked up fuse and realized that I had inadvertently rolled back FUSE3. So I switched to a terminal in text mode by pressing “Alt + F2”, logged in, and reinstalled FUSE3. However I also noticed that it didn’t involve installing a huge number of other packages but one thing at a time. I rebooted.
Of course I was still left in the system console after rebooting, with gdm loading but me not seeing a GUI. So again I switched to a terminal, and thought about what my next step was going to be, and fortunately I found that apt has a flag you can use to reinstall some parts of the system (–reinstall). So at that point I started looking for a “desktop” meta-package and immediately saw “ubuntu-desktop”, so I went for it with this command:
“sudo apt install –reinstall ubuntu-desktop”
and this operation took care of all the dependencies. I crossed my fingers, rebooted, and Hallelujah! I got my desktop back, and my first thought was “I gotta write this down”, that’s the technical writer in me I guess.
Fortunately Ubuntu has the ubuntu-desktop metapackage available. Had this happened with another distro I think recovery would not have been nearly as easy And fortunately I remembered exactly what I had done at the system level which could have caused this problem. Because, make no mistake, I am the only person who caused that problem.
However it might be a good idea to “blacklist” the fuse package from getting installed by apt, as this really shouldn’t be done by anyone who’s running the Ubuntu desktop. I’m not exactly sure how this could be done, but it’d be a good idea.
That being said, and even better idea is to be careful AS ONE SHOULD BE when installing packages using sudo and apt, and to not just breeze through stuff because of a foolish sense of self-assurance that “I know what I’m doing”. And that’s ultimately the lesson from this — sudo as a tool is powerful, and the way it works on Linux is to add a step (authentication) that’s literally there to stop you from doing something stupid. In Breaking Bad the expression “respect the chemistry” keeps coming up. Well, if you’re using Linux, remember to “respect the permissions”. But, if you do get yourself into trouble, at least Linux is made in such a way that it’s possible to walk back your errors and get back to a working system, which is more than I can say for Windows.