Not sure if this is related but "pacman -Syu" on my GoFlex Home also errors with the following:
$this->bbcode_second_pass_code('', '
Targets (14): filesystem-2012.6-2  git-1.7.10.4-1  gnutls-3.0.20-1
              initscripts-2012.06.1-1  krb5-1.10.2-1  libcups-1.5.3-4
              libwbclient-3.6.5-3  linux-api-headers-3.3.8-1  openntpd-3.9p1-15
              pacman-mirrorlist-20120608-1  psmisc-22.17-1  samba-3.6.5-3
              smbclient-3.6.5-3  systemd-tools-185-1
Total Installed Size:   141.92 MiB
Net Upgrade Size:       0.12 MiB
Proceed with installation? [Y/n]
(14/14) checking package integrity                 [######################] 100%
(14/14) loading package files                      [######################] 100%
(14/14) checking for file conflicts                [######################] 100%
error: failed to commit transaction (conflicting files)
filesystem: /var/lock exists in filesystem
filesystem: /var/run exists in filesystem
Errors occurred, no packages were upgraded.
')
EDIT:  It seems this is an issue across the archlinux platform with a solution posted 
here.