ArchLinux - Pacman error: $filename exists in filesystem

Before each update, check Archlinux news, there may be special instructions.

When updating you system with # pacman -Syu you may sometimes encounter this error:

error: could not prepare transaction
error: failed to commit transaction (conflicting files)
libname: /absolut/file/path exists in filesystem
Errors occurred, no packages were upgraded.

pacman has detected a file conflict, and is preventing you to overwrite those files. So it's user responsability to take a decision.

To solve this you have to check that those files are not used by any installed package with the command: $ pacman -Qo /absolut/file/path.

If no package is using the file you will get this normal error:

$ pacman -Qo /absolut/file/path
error: No package owns /absolut/file/path

Now you can rename the file (mv /path/file.ext /path/file.ext.bck), then try the update again # pacman -Syu and then remove the, now, useless file (rm /path/file.ext.bck).

But if the file is used report a bug.