Yaru theme installed but not enabled by default nor available after upgrade to Cosmic

[Yassine]

I have recently upgraded from 18.04 LTS to 18.10, but the Yaru theme is not enabled by default nor available to choose in GNOME Tweaks, even though apt says it is already installed. I had the communitheme snap installed when I was using 18.04 LTS, but it stopped working after the upgrade.

$ lsb_release -rd
Description: Ubuntu 18.10
Release: 18.10

$ apt-cache policy yaru-theme-gnome-shell yaru-theme-gtk
yaru-theme-gnome-shell:
  Installed: 18.10.6
  Candidate: 18.10.6
  Version table:
 *** 18.10.6 500
        500 http://archive.ubuntu.com/ubuntu cosmic/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu cosmic/main i386 Packages
        100 /var/lib/dpkg/status
yaru-theme-gtk:
  Installed: 18.10.6
  Candidate: 18.10.6
  Version table:
 *** 18.10.6 500
        500 http://archive.ubuntu.com/ubuntu cosmic/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu cosmic/main i386 Packages
        100 /var/lib/dpkg/status

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Sebastien Bacher (seb128)]

What session are you using?

[Daniel van Vugt (vanvugt)]

^^^
Seb is probably asking if you are using a Wayland session. If so then bug 1799205 might be relevant.

[Yassine (yassine10suno)]

Bug exists in both X.Org and Wayland. I tried them both.

[Yassine (yassine10suno)]

Turns out GNOME Tweaks caused this. I restored default settings in GNOME Tweaks, then I logged out, and in a tty, I reinstalled ubuntu-session and every part of the yaru theme:

sudo apt purge ubuntu-session yaru-theme-gnome-shell yaru-theme-gtk yaru-theme-icon yaru-theme-sound
sudo apt install ubuntu-session yaru-theme-gnome-shell yaru-theme-gtk yaru-theme-icon yaru-theme-sound

then after logging in, all the themes were applied correctly.

[Launchpad Janitor (janitor)]

[Expired for yaru-theme (Ubuntu) because there has been no activity for 60 days.]

[Daniel van Vugt (vanvugt)]

Sounds like it was bug 1799205, which is now fixed.

Please let us know if the problem persists.

[Tofik Sonono (tsonono)]

I just want to add. I installed the LTS version today and encountered this bug. I did what Yassine suggested and that resolved the issue.

[Muhammad Sahim Bhaur (sahim5734)]

Yassine (yassine10suno) that helped in Ubuntu 20 LTS too! Thanks! I just followed exactly that and it worked perfectly.