Comment # 42 on bug 1183727 from John Carrick Smith

Created attachment 853572 [details]
System journals

I have tried with WiFi disconnected from any SSID and also with WIFI stopped.
On both occasions the shutdown hung for approximately 90 seconds firstly with
the last message
 "Started Show Plymouth Power Off Screen" 
and then again at
 "Stopped Name Service Cache Daemon".

Then, when the last message was
 "Reached Target Shutdown"
it hung for longer than my patience would tolerate and I used the power button
to complete the shut-down.

There are two journals in the attached archive with the names:
"jrnlwifidiscon" - Wifi active but not connected to any SSID, and 
"jrnlnowifi" - Wifi deactivated.

Thanks. John