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The root problem is that both these packages contains the file '/usr/bin/disco' which cause issues when attempting to install both at the same time. See also the corresponding Debian bug report. https://packages.ubuntu.com/hirsute/all/mono-devel/filelist https://packages.ubuntu.com/hirsute/all/discodos/filelist ** Also affects: discodos (Ubuntu) Importance: Undecided Status: New ** Bug watch added: Debian Bug tracker #966115 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=966115 ** Also affects: discodos (Debian) via https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=966115 Importance: Unknown Status: Unknown ** Changed in: mono (Ubuntu) Status: New => Confirmed ** Changed in: discodos (Ubuntu) Status: New => Confirmed ** Tags added: package-conflict -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1928414 Title: Ubuntu 21.04 mono-devel_6.8.0.105+dfsg-3_all.deb install failed To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/discodos/+bug/1928414/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs