when i run fix broken install : E: Sub-process dpkg --set-selections returned an error code (100) E: Couldn't clean the currently selected dpkg states

Question

I am using ubuntu 24.04 LTS . I am using kernal version 6.8.0-39-generic I am running 64bit x86 architecture.

first when i run this code i am getting error of unmet dependencies:

user@omkar:~$ sudo apt upgrade
[sudo] password for user: 
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
 wpasupplicant : Depends: libc6 (>= 2.34) but it is not installed
                 Depends: libdbus-1-3 (>= 1.9.14) but it is not installed
                 Depends: libnl-3-200 (>= 3.2.21) but it is not installed
                 Depends: libnl-genl-3-200 (>= 3.2.7) but it is not installed
                 Depends: libnl-route-3-200 (>= 3.4.0) but it is not installed
                 Depends: libpcsclite1 (>= 1.0.0) but it is not installed
                 Depends: libreadline8t64 (>= 6.0) but it is not installed
                 Depends: libssl3t64 (>= 3.0.0) but it is not installed
                 Depends: adduser but it is not installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).

so after i tried sudo apt --fix-broken install , and again i got new error :

user@omkar:~$ sudo apt --fix-broken install 
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Correcting dependencies... Done
The following additional packages will be installed:
  adduser apt apt-utils ca-certificates dbus dbus-bin dbus-daemon
  dbus-session-bus-common dbus-system-bus-common debconf debconf-i18n dpkg
  gcc-14-base gpgv libacl1 libapparmor1 libapt-pkg6.0t64 libassuan0
  libaudit-common libaudit1 libbz2-1.0 libc6 libcap-ng0 libcap2 libcrypt1
  libdb5.3t64 libdbus-1-3 libexpat1 libffi8 libgcc-s1 libgcrypt20 libgmp10
  libgnutls30t64 libgpg-error-l10n libgpg-error0 libhogweed6t64 libidn2-0
  liblocale-gettext-perl liblz4-1 liblzma5 libmd0 libnettle8t64 libnl-3-200
  libnl-genl-3-200 libnl-route-3-200 libnpth0t64 libp11-kit0 libpam-modules
  libpam-modules-bin libpam0g libpcre2-8-0 libpcsclite1 libreadline8t64
  libseccomp2 libselinux1 libsemanage-common libsemanage2 libsepol2 libssl3t64
  libstdc++6 libsystemd0 libtasn1-6 libtext-charwidth-perl libtext-iconv-perl
  libtext-wrapi18n-perl libtinfo6 libudev1 libunistring5 libxxhash0 libzstd1
  openssl passwd perl-base readline-common sensible-utils tar ubuntu-keyring
  zlib1g
Suggested packages:
  perl cron quota ecryptfs-utils apt-doc aptitude | synaptic | wajig dpkg-dev
  gnupg | gnupg2 | gnupg1 powermgmt-base default-dbus-session-bus
  | dbus-session-bus debconf-doc debconf-kde-helper debconf-utils libgtk3-perl
  libnet-ldap-perl libterm-readline-gnu-perl whiptail | dialog debsig-verify
  gnupg glibc-doc locales libnss-nis libnss-nisplus rng-tools gnutls-bin
  libpam-doc pcscd readline-doc bzip2 ncompress xz-utils tar-scripts tar-doc
The following NEW packages will be installed:
  adduser apt apt-utils ca-certificates dbus dbus-bin dbus-daemon
  dbus-session-bus-common dbus-system-bus-common debconf debconf-i18n dpkg
  gcc-14-base gpgv libacl1 libapparmor1 libapt-pkg6.0t64 libassuan0
  libaudit-common libaudit1 libbz2-1.0 libc6 libcap-ng0 libcap2 libcrypt1
  libdb5.3t64 libdbus-1-3 libexpat1 libffi8 libgcc-s1 libgcrypt20 libgmp10
  libgnutls30t64 libgpg-error-l10n libgpg-error0 libhogweed6t64 libidn2-0
  liblocale-gettext-perl liblz4-1 liblzma5 libmd0 libnettle8t64 libnl-3-200
  libnl-genl-3-200 libnl-route-3-200 libnpth0t64 libp11-kit0 libpam-modules
  libpam-modules-bin libpam0g libpcre2-8-0 libpcsclite1 libreadline8t64
  libseccomp2 libselinux1 libsemanage-common libsemanage2 libsepol2 libssl3t64
  libstdc++6 libsystemd0 libtasn1-6 libtext-charwidth-perl libtext-iconv-perl
  libtext-wrapi18n-perl libtinfo6 libudev1 libunistring5 libxxhash0 libzstd1
  openssl passwd perl-base readline-common sensible-utils tar ubuntu-keyring
  zlib1g
0 upgraded, 78 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/22.6 MB of archives.
After this operation, 77.5 MB of additional disk space will be used.
Do you want to continue? [Y/n] y
E: Cannot get debconf version. Is debconf installed?
debconf: apt-extracttemplates failed: 25600
Extracting templates from packages: 38%E: Cannot get debconf version. Is debconf installed?
debconf: apt-extracttemplates failed: 25600
Extracting templates from packages: 76%E: Cannot get debconf version. Is debconf installed?
debconf: apt-extracttemplates failed: 25600
Extracting templates from packages: 100%
E: Sub-process dpkg --set-selections returned an error code (100)
E: Couldn't clean the currently selected dpkg states

In this error , is asking is debconf installed , so i tried to install debconf but it showing you have unmet dependencies :

user@omkar:~$ sudo apt-get install debconf
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
 wpasupplicant : Depends: libc6 (>= 2.34) but it is not going to be installed
                 Depends: libdbus-1-3 (>= 1.9.14) but it is not going to be installed
                 Depends: libnl-3-200 (>= 3.2.21) but it is not going to be installed
                 Depends: libnl-genl-3-200 (>= 3.2.7) but it is not going to be installed
                 Depends: libnl-route-3-200 (>= 3.4.0) but it is not going to be installed
                 Depends: libpcsclite1 (>= 1.0.0) but it is not going to be installed
                 Depends: libreadline8t64 (>= 6.0) but it is not going to be installed
                 Depends: libssl3t64 (>= 3.0.0) but it is not going to be installed
                 Depends: adduser but it is not going to be installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).

It is all going like a circle , i am unable to fix this errors.

Answer 1

It looks like you are getting an unmet dependencies error message that is preventing you from installing debconf because you don't have default software sources in your /etc/apt/sources.list.d/ubuntu.sources To restore the default software sources in your ubuntu.sources file follow the instructions in this answer.

To fix the common malformed line 1 in source list /etc/apt/sources.list.d/ubuntu.sources error please visit the canonical How do I remove a malformed line from my sources.list? question. Please take note that /etc/apt/sources.list in old versions of Ubuntu has been updated to /etc/apt/sources.list.d/ubuntu.sources in Ubuntu 24.04 (and later).

1. Check if debconf is installed by running apt policy debconf If debconf is not installed then install it with sudo apt install debconf

2. Verify debconf configuration by running sudo dpkg-reconfigure debconf

3. Update the package list by running sudo apt update

4. Try running sudo apt upgrade again and see if you get any error message about unmet dependencies Please edit your question and add the results of sudo apt upgrade This will help me to resolve the unmet dependencies if you are still getting an error message about unmet dependencies. My intuition tells me that you will still have remaining unmet dependencies after following these four steps. If so, I will add more information to this answer.