Data Domain: Upgrade Failing with Error "Upgrade already in progress"

The following error message is received when trying to upgrade:

# system upgrade 6.2.1.30-663869.rpm
    ** This command is deprecated and will be unavailable in future releases.
    Use 'system upgrade start' or 'system upgrade precheck' instead.

    The 'system upgrade' command upgrades the Data Domain OS. File access
    is interrupted during the upgrade. The system reboots automatically
    after the upgrade.
    Are you sure? (yes|no) [no]: yes

    ok, proceeding.

    **** Upgrade failed: another upgrade is in progress.

[messages.engineering]
Oct 13 13:07:58 localhost reg_async[29701]: NOTICE: Run: chroot /ddr/aspirin-rootfs-CentOS/ /bin/bash -c 'while ip rule delete table tethMa 2>/dev/null; do :; done; exit 0;' 2>&1
Oct 13 13:08:02 localhost ntpd[28156]: ntpd exiting on signal 15 (Terminated)
Oct 13 13:08:31 localhost reg_async[29701]: INFO: sms_net_route_n_rules_add_n_del: Executing: /bin/bash -c 'while ip rule delete table tethMa 2>/dev/null; do :; done; exit 0;'
Oct 13 13:08:31 localhost reg_async[29701]: NOTICE: Run: chroot /ddr/aspirin-rootfs-CentOS/ /bin/bash -c 'while ip rule delete table tethMa 2>/dev/null; do :; done; exit 0;' 2>&1
Oct 13 13:08:35 localhost ntpd[5250]: ntpd exiting on signal 15 (Terminated)
Oct 13 14:03:44 localhost ddsh: NOTICE: cmd scp -t /ddr/var/releases/ exited with 0:
Oct 13 14:05:02 localhost ddsh: NOTICE: MSG-DDSH-00017: autosupport: command "ddboost fc group show detailed" exited with code: 41
Oct 13 14:20:14 localhost ddsh: NOTICE: MSG-DDSH-00017: (tty=pts/0, session=20294) root: command "system upgrade 6.2.1.30-663869.rpm" exited with code: 607
Oct 13 14:24:18 localhost ddsh: NOTICE: MSG-DDSH-00017: (tty=pts/0, session=20294) root: command "system upgrade precheck status" exited with code: 607

1. Verify that the HA pair is properly configured using a CIFS share or NFS export. Check for the following file and remove it:

/ddvar/lock/upgrade_lock

2. Restart the update.