I did the update per the fedoraproject.org wiki:
1.  yum update yum
2. yum clean all
3. yum --releasever=18 --disableplugin=presto distro-sync
4. rpm --rebuilddb


I removed "rhgb quiet" and here's where the bootup stalls:
           Starting Authorization Manager...
OK    Started Login Service.
OK    Started Avahi mDNS/DNS-SD Stack.
FAILED    Failed to start Authorization Manager.
See 'systemctl status polkit.service' for details.
OK    Started ACPI Event Daemon.
OK    Started IPv6 firewall with ip6tables.
OK    Stated GNOME Display Manager.
OK    Started LSB: VirtualBox Linux kernel module.
            Started LSB: VirtualBox web service API...
            Started LSB: VirtualBox balloon control daemon...
OK    Started LSB: VirtualBox web service API.
OK    Started LSB: VirtualBox balloon control daemon.
54.411404    r8169 0000:07:01.0 em1: link down
54.411594    IPv6: ADDRCONF(NETDEV_UP): em1: link is not ready
54.412780    r8169 0000:07:01.0 em1: link down
54.473537    ppdev: user-space parallel port driver
54.506406    NFSD: starting 90-second grace period
56.010158    r8169 0000:07:01.0 em1: link up
56.010321    IPv6: ADDRCONF(NETDEV_CHANGE): em1 :link becomes ready
94.170588    traps: packagekitd[6139] trap int3 ip:7fc584637c67 sp:7fffdeb65000 error:0
123.321944    traps: packagekitd[6260] trap int3 ip:7f497a99ac67 sp:7fff1b15b6d0 error:0



From: JUSTIN TAYLOR <justay@swbell.net>
To: users@lists.fedoraproject.org
Sent: Thursday, January 23, 2014 6:36 PM
Subject: Re: Fedup F17 --> F20



Well, I wasn't able to find an F18 ISO (guess I wasn't asking Google nicely enough).  So, I tried a yum upgrade to F18.  Everything looked OK until I rebooted.  It gets to the blue bar that moves across the bottom (it says Fedora 18).  Then my PC reboots.  Normally, I would boot into recovery mode using the disk, but here I don't have one.

Any ideas how to diagnose/fix this?


------------------------------
On Sun, Jan 5, 2014 8:28 PM CST Eddie G. O'Connor Jr. wrote:

>On 01/05/2014 10:01 AM, JUSTIN TAYLOR wrote:
>> Sorry about leaving off the subject...  I had a brain fart I guess.
>>
>> So F17 doesn't support fedup huh?  A little odd since yum installed it
>> for me.  But no matter,  I'll download an F18 ISO when I get the chance.
>>
>>
>> Thank you very much!
>>
>>
>>
>>
>> ------------------------------------------------------------------------
>> *From:* Frank Murphy <frankly3d@gmail.com>
>> *To:* Frank Murphy <frankly3d@gmail.com>
>> *Cc:* users@lists.fedoraproject.org; JUSTIN TAYLOR <justay@swbell.net>
>> *Sent:* Sunday, January 5, 2014 8:27 AM
>> *Subject:* Re: Fedup F17 --> F20
>>
>> On Sun, 5 Jan 2014 14:22:35 +0000
>> Frank Murphy <frankly3d@gmail.com <mailto:frankly3d@gmail.com> wrote:
>>
>>
>> > You can't use fedup to go from F17 --> F20 in one go.
>> > You would need to go to F18 first then maybe F20
>> >
>>
>> Actually fedup want' available for F17, preupgrade was the method.
>> fedup was fro F18+
>>
>>
>>
>> ___
>> Regards,
>> Frank
>> www.frankly3d.com
>>
>>
>>
>>
>>
>I would even go further and say you'd be better off going from F18 to
>F19...and THEN going from F19 to F20.....(I had a few problems going
>F18-->F20....but when I went from F18-->F19-->F20....things seemed to go
>smoother!) just my two cents...
>
>
>EGO II