Updating MSYS2

After you have installed MSYS2 via the installer or other means, you need to continue updating it with the built-in pacman tool. MSYS2 is a rolling release distribution and only supports full system upgrades, which means there are frequent minor and major updates to various packages and you can only update all packages at once.

To update all packages run the following command:

$ pacman -Suy
:: Synchronizing package databases...
 mingw32 is up to date
 mingw64 is up to date
 ucrt64 is up to date
 clang32 is up to date
 clang64 is up to date
 msys is up to date
:: Starting core system upgrade...
 there is nothing to do
:: Starting full system upgrade...
 there is nothing to do

In some cases, certain core packages will get updated and pacman will prompt you to close all terminals:

:: To complete this update all MSYS2 processes including this terminal will be closed.
   Confirm to proceed [Y/n]

After confirming you need to start a new terminal and run the update again (pacman -Suy) to update the remaining non-core packages.

Optional Maintenance Tasks

Pruning the package cache

pacman keeps all packages it downloads under /var/cache/pacman/pkg/. To free up some space by removing old packages run:

$ paccache -r
==> finished: 5 packages removed (disk space saved: 49.05 MiB)

Managing configuration file backups

When you have modified a global configuration file of a package (under /etc for example) and the package is about to be removed or updated then pacman will avoid deleting your changes. The pacdiff tool can then be used to merge your configuration file with the default state again.

1) In case a new package version with some changed configuration gets installed, which would discard your changes, pacman will leave the existing file alone and create a <filename>.pacnew with the new configuration instead:

warning: /etc/myconfig.conf installed as /etc/pacman.d/myconfig.conf.pacnew

You can run pacdiff which searches for such .pacnew files and will ask you how it should deal with them:

$ pacdiff
==> pacnew file found for /etc/myconfig.conf
:: (V)iew, (M)erge, (S)kip, (R)emove pacnew, (O)verwrite with pacnew, (Q)uit: [v/m/s/r/o/q]

2) In case the configuration file is part of a package which gets uninstalled it will save a copy as <filename>.pacsave instead of deleting it:

warning: /etc/myconfig.conf saved as /etc/myconfig.conf.pacsave

If you later on install the package again you can run pacdiff to restore your original changes:

$ pacdiff
==> pacsave file found for /etc/myconfig.conf
:: (V)iew, (M)erge, (S)kip, (R)emove pacsave, (O)verwrite with pacsave, (Q)uit: [v/m/s/r/o/q]

Pruning unsupported packages

In some cases we decide to drop packages from the repositories, for example because they are outdated, unmaintained or have been replaced by a better alternative. If you've installed them previously then they will stay installed but wont get updated anymore. To find such packages you can run:

$ pacman -Qm

It might be a good idea to remove them, or look for alternatives if you still need them.

Potential Issues

If you haven't updated MSYS2 for more than half a year then you could end up in a state where an update would require a new or updated package maintainer's signature key but you haven't gotten it through an update yet. This will lead to pacman failing to verify the package or database signatures:

$ pacman -S lftp
[...]
error: lftp: signature from "Some MSYS2 Maintainer <some.msys2.maintainer@gmail.com>" is unknown trust
:: File /var/cache/pacman/pkg/lftp-4.9.2-3-x86_64.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n]

To get back to a working state you can run pacman-key --refresh-keys, which updates the package maintainer keys you already have installed.

In case that doesn't help because a new key is required, you can do a partial upgrade of the keyring to get the missing key, followed by a full upgrade: pacman -Sy msys2-keyring; pacman -Suy