A number of users have reported an issue in which Mac OS X 10.6.x (Snow Leopard) is slow to go to sleep. In these cases, the system will stay awake for 30 seconds to several minutes before entering sleep mode.
Fixes
Check printer queue. This problem may be caused by items stuck in the print queue. Go to http://127.0.0.1:631/jobs/, which will show all current print jobs. Cancel any stuck items, then re-attempt sleep.
You should also go to Print & Fax in System Preferences and remove any printers that you no longer use.
Disconnect external devices. Errant external devices, particularly USB drives and other peripherals, as well as iPods, iPhones and iPads, can cause a delay in sleep. Disconnect any peripherals then re-attempt sleep.
Check for hung processes. Launch the Activity Monitor (click the Spotlight [magnifying glass] icon in the upper right corner of the screen and type Activity Monitor), then sort the items by the CPU tab. Quit any items not in use that are using significant processor time.
Feedback? info@appletoolbox.com.
Nicholas on 
Lawrence Alonzo on 
rickyc on 
Carnghamcats on 
Deb Santagata on 
MARK on 
Shafqat Zaman on 
AppleID:( on 
July 9, 2010 at 9:56 PM
In my case the culprit is Safari 5.0. When left open system is slow to sleep. When I quit Safari prior to Sleep command, response time is typical.
August 30, 2010 at 2:58 AM
Checking the printer queue solved my slow sleep problem. I deleted the stuck item and now my mac goes to sleep as if it were new.
Many thanks
March 18, 2011 at 5:51 AM
Just as Souki said. Clear the print queue and we sleep like a baby. Thanks for the tip.
May 22, 2011 at 5:11 AM
Clearing the print queue via the link worked. Brilliant!
30 sec down to instant
There was a print queue but no printer in the printer pref pane. Odd.
Using Terminal, this command shows (among other things) processes preventing sleep.
pmset -g log
e.g.
* Domain: applicationresponse.timedout
– Message: Kernel cupsd com.apple.powermanagement.applicationresponse.timedout 30000 ms
– Time: 22/05/2011 12:40:04 GMT+01:00
– Signature: cupsd
– UUID: 77A2A38B-7669-4F60-AF3E-897CA04B5A99
– Result: Noop
– Response time (ms): 30000
May 29, 2011 at 9:34 PM
Thanks for the tip. Quick solution. I connect to different printers and might forget to delete a job if a particular printer isn’t available. Print queue lives on.
June 15, 2011 at 3:14 PM
Clearing the printer queue worked for me too. Thanks!