Error “cannot resolve dependency lib32 (32-bit library)” (SOLVED)

When installing a package on Arch Linux or a distro derived from it, for example, by running the following command:

sudo pacman -S trid

an error may occur stating that dependencies could not be resolved. The name of this dependency can contain the number “32” or the string “lib32”, that is, it is a 32-bit package, for example:

resolving dependencies...
warning: cannot resolve "lib32-ncurses", a dependency of "trid"
:: The following package cannot be upgraded due to unresolvable dependencies:
      trid

:: Do you want to skip the above package for this upgrade? [y/N]

To fix this error, multilib must be enabled.

The multilib repository is the official repository that allows the user to run and build 32-bit applications on 64-bit Arch Linux.

To enable multilib, open the text file /etc/pacman.conf:

sudo gedit /etc/pacman.conf

Find and uncomment the lines in it (make sure to uncomment both lines, otherwise the changes will not take effect):

[multilib]
Include = /etc/pacman.d/mirrorlist

Update package information:

sudo pacman -Sy

And re-run the package installer – this time all dependencies should be resolved.