I am not sure what you have posted, Maurice so am I right in assuming that your network connection is not properly killall which is why your shutdown process is taking too long, waiting for these processes (network, avahi-daemon) to be closed?
Yes, Archie, it seems so from the loops I'm getting. But the shutdown is not just taking too long - it doesn't shutdown at all.
Let me explain a little bit... your system is not shutting down properly therefore the filesystem is not getting umounted correctly either, which might eventually lead to a compromised system integrity ... in short, this is definitely not good.
For the filesystem to be correctly umounted, there is a killall for all the processes, and in your case killall is ineffective to one or two of your running processes. We know its something in Network.
Do you have samba shares mounted? Are you using wireless or wired?
There's a couple of things I want you to try ... on a terminal (don't be afraid) ...
[user@localhost ~]$ ifconfig [Enter]
and tell us the output ... only need to know if it's eth0 or eth1 or wlan0 or maybe even something else unusual.
Before shutting down, try the command
[root@localhost ~]# ifdown <network_device> [Enter] //where <network_device> is either eth0, eth1, wlan0, etc.
The tell us what happened on your next reboot.
Samba shares -- No
Wireless -- wlan0
Ain't afraid of the terminal Archie.
[mihi@localhost ~]$ ifconfig
eth0 Link encap:Ethernet HWaddr 00:1C:C0:38:A8:77
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:78 errors:0 dropped:0 overruns:0 frame:0
TX packets:78 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:3900 (3.8 KiB) TX bytes:3900 (3.8 KiB)
wlan0 Link encap:Ethernet HWaddr 00:25:9C:A8:72:DE
inet addr:10.0.0.7 Bcast:10.0.0.255 Mask:255.255.255.0
inet6 addr: fe80::225:9cff:fea8:72de/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:25290 errors:0 dropped:0 overruns:0 frame:0
TX packets:22275 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:22670457 (21.6 MiB) TX bytes:5378547 (5.1 MiB)
[root@localhost mihi]# ifdown wlan0
My connection dropped when I typed this command but it may have been something else
When I turned the machine off it shut down first time. My next reboot was as normal.