While upgrading Arch Linux

sudo pacman -Syu

I run into this problem

error: failed to commit transaction (conflicting files)
cups: /etc/cups/classes.conf exists in filesystem
cups: /etc/cups/printers.conf exists in filesystem
cups: /etc/cups/subscriptions.conf exists in filesystem
Errors occurred, no packages were upgraded.

To solve it, just backup all files that are causing the problem.

cp /etc/cups/classes.conf /etc/cups/classes.conf.original

cp /etc/cups/printers.conf /etc/cups/printers.conf.original

cp /etc/cups/subscriptions.conf /etc/cups/subscriptions.conf.original

Then upgrade cups with force switch

sudo pacman -Sf cups

The output could be:

resolving dependencies...
looking for inter-conflicts...

Targets (2): libcups-1.4.3-2  cups-1.4.3-2  

Total Download Size:    0.00 MB
Total Installed Size:   14.54 MB

Proceed with installation? [Y/n] y
checking package integrity...
(1/2) upgrading libcups                             [#########################################################################################################################################################] 100%
(2/2) upgrading cups                                [#########################################################################################################################################################] 100%
warning: /etc/cups/classes.conf installed as /etc/cups/classes.conf.pacnew
warning: /etc/cups/subscriptions.conf installed as /etc/cups/subscriptions.conf.pacnew
warning: /etc/cups/printers.conf installed as /etc/cups/printers.conf.pacnew

Then run again

sudo pacman -Syu

It should work this time.