[Bug 2150296] Re: Cannot install gcc, clang, or build-essential on fresh install of Ubuntu Resolute

Sat Apr 25 10:33:32 UTC 2026

> P.S. is there a way to view the status of a mirror?

All the default mirrors should work. It's a bug if the installer chooses
a bad mirror.

I opened a ticket at https://rt.ubuntu.com/Ticket/Display.html?id=88423
. I used Docker ubuntu:26.04 to confirm this problem still occurs after
switching /etc/apt/sources.list.d/ubuntu.sources to
th.archive.ubuntu.com .

** Bug watch added: rt.ubuntu.com/ #88423
   https://rt.ubuntu.com/Ticket/Display.html?id=88423

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https://bugs.launchpad.net/bugs/2150296

Title:
  Cannot install gcc, clang, or build-essential on fresh install of
  Ubuntu Resolute

Status in Ubuntu:
  New
Status in apt package in Ubuntu:
  New

Bug description:
  On fresh install of Ubuntu 26.04 LTS with official ISO, I am unable to
  install C compiling/building related packages, including but not
  limited to gcc, clang, or build-essential.

  * Install gcc: sudo apt install build-essential

  Expected result: the package is installed normally.
  Actual result: APT shows dependencies error instead.

  $ lsb_release -rd
  Description:	Ubuntu 26.04 LTS
  Release:	26.04

  $ sudo apt install gcc
  [sudo: authenticate] Password:                 
  Solving dependencies... Error!  
  Some packages could not be installed. This may mean that you have
  requested an impossible situation or if you are using the unstable
  distribution that some required packages have not yet been created
  or been moved out of Incoming.
  The following information may help to resolve the situation:

  Unsatisfied dependencies:
   gcc : Depends: gcc-15 (>= 15.2.0-2~) but it is not going to be installed
         Depends: gcc-x86-64-linux-gnu (= 4:15.2.0-5ubuntu1) but it is not going to be installed
  Error: Unable to satisfy dependencies. Reached two conflicting assignments:
     1. gcc:amd64=4:15.2.0-5ubuntu1 is selected for install
     2. gcc:amd64 Depends gcc-15 (>= 15.2.0-2~)
        but none of the choices are installable:
        - gcc-15:amd64 Depends gcc-15-base (= 15.2.0-12ubuntu1)
          but none of the choices are installable:
          - gcc-15-base:amd64=15.2.0-12ubuntu1 is not selected for install

  $ sudo apt install clang
  Solving dependencies... Error!  
  Some packages could not be installed. This may mean that you have
  requested an impossible situation or if you are using the unstable
  distribution that some required packages have not yet been created
  or been moved out of Incoming.
  The following information may help to resolve the situation:

  Unsatisfied dependencies:
   clang : Depends: clang-21 (>= 1:21.1.6-1) but it is not going to be installed
  Error: Unable to satisfy dependencies. Reached two conflicting assignments:
     1. clang:amd64=1:21.1.6-70 is selected for install
     2. clang:amd64 Depends clang-21 (>= 1:21.1.6-1)
        but none of the choices are installable:
        - clang-21:amd64 Depends libllvm21 (= 1:21.1.8-1ubuntu1)
          but none of the choices are installable:
          - libllvm21:amd64=1:21.1.8-1ubuntu1 is not selected for install

  $ sudo apt install build-essential 
  Solving dependencies... Error!  
  Some packages could not be installed. This may mean that you have
  requested an impossible situation or if you are using the unstable
  distribution that some required packages have not yet been created
  or been moved out of Incoming.
  The following information may help to resolve the situation:

  Unsatisfied dependencies:
   build-essential : Depends: gcc (>= 4:14.2) but it is not going to be installed
                     Depends: g++ (>= 4:14.2) but it is not going to be installed
                     Depends: make
                     Depends: dpkg-dev (>= 1.22.11) but it is not going to be installed
  Error: Unable to satisfy dependencies. Reached two conflicting assignments:
     1. build-essential:amd64=12.12ubuntu2 is selected for install
     2. build-essential:amd64 Depends gcc (>= 4:14.2)
        but none of the choices are installable:
        - gcc:amd64 Depends gcc-15 (>= 15.2.0-2~)
          but none of the choices are installable:
          - gcc-15:amd64 Depends gcc-15-base (= 15.2.0-12ubuntu1)
            but none of the choices are installable:
            - gcc-15-base:amd64=15.2.0-12ubuntu1 is not selected for install

  There also seem to have gcc-15-base, and gcc-16-base installed on the
  system already, which I suspect is the one causing the conflict.

  $ apt list --installed | grep gcc

  WARNING: apt does not have a stable CLI interface. Use with caution in
  scripts.

  gcc-15-base/now 15.2.0-16ubuntu1 amd64 [installed,local]
  gcc-16-base/now 16-20260322-1ubuntu1 amd64 [installed,local]
  libgcc-s1/now 16-20260322-1ubuntu1 amd64 [installed,local]

  ProblemType: Bug
  DistroRelease: Ubuntu 26.04
  Package: gcc (not installed)
  ProcVersionSignature: Ubuntu 7.0.0-14.14-generic 7.0.0
  Uname: Linux 7.0.0-14-generic x86_64
  ApportVersion: 2.34.0-0ubuntu2
  Architecture: amd64
  CasperMD5CheckResult: pass
  CurrentDesktop: ubuntu:GNOME
  Date: Sat Apr 25 12:21:41 2026
  InstallationDate: Installed on 2026-04-25 (0 days ago)
  InstallationMedia: Ubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423.1)
  ProcEnviron:
   LANG=en_US.UTF-8
   PATH=(custom, no user)
   SHELL=/bin/bash
   TERM=xterm-256color
   XDG_RUNTIME_DIR=<set>
  SourcePackage: gcc-defaults
  UpgradeStatus: No upgrade log present (probably fresh install)

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