Fix Printer Queue Glitches
When your printer won't print, sometimes you'll try the basics of printer troubleshooting with no results. Whether your printer's Dock icon bounces endlessly or a message says you're stuck at "connecting," here's how to handle problems with your printer queue.
The ever-bouncing Dock icon
Instead of a freshly printed page sitting in your printer tray, all you see is the Dock icon for your printer bouncing up and down. What now? That Dock icon represents your printer's queue (in other words, the list of jobs waiting to print). You might also see a yellow triangle with an exclamation mark image on the icon. This alert shows that the printing process has gone awry. To find out more, click on the Dock icon. The Queue window should open and, with luck, contain a message that describes the cause of the printing failure. If the message refers to your paper tray or ink levels, follow the aforementioned instructions for resolving those problems. If the message offers other clear advice (such as to click on Resume), follow it.
Delete old jobs and reset Otherwise, select the name of the print job in the Queue window and click on Delete in the toolbar. If other, older print jobs are also listed, delete them as well. When you're done, the status message in the Queue window should say "Printer Ready."
As an extra precaution, turn your printer off and back on again. This "resets" the printer, potentially correcting any trouble at the printer's end. Now go back to your application and try printing once more.
Check the error log If that doesn't work, select Printer -> Log & History while the Queue window is open. This launches Console and takes you directly to the printer error_log file (in your hard drive's /var/log/cups directory). The messages in this log, while often beyond the understanding of mere mortals, occasionally point to the precise cause of your problem. For example, the log once identified an improperly installed ink cartridge in my inkjet printer. I removed and reinstalled the cartridge--printing problem gone!
Tip: To open a printer's Queue window at any time, even if its icon is not in the Dock, go the Print & Fax system preference, select the printer's name, and click on Open Print Queue.
Stuck at "connecting"
Sometimes, the printer icon shows up in the Dock, but it doesn't bounce. Instead, when you go to the Queue window, the status message seems stuck at "Connecting." In this case, your Mac is probably unable to locate the printer. We've already covered the simplest reason for this: the printer isn't on. Make sure it is. Also make sure that your printer is connected properly and that there isn't a paper jam. If your printer is in some sort of "offline" state (a message on the printer's display will typically tell you if this is the case), turn it off and back on again.
Prevent shared-printer problems If you share your printer over a network, you need to perform some other quick checks. First, go to the Mac that's connected to the printer and confirm that the Mac is on and not asleep. Next, open System Preferences on the Mac and take a look at the Sharing system preference. Confirm that the Printer Sharing option is enabled here. Next, look at the Print & Fax system preference and make sure the Share This Printer option is enabled.
Beat wireless woes If the printer is connected to your Mac over a wireless network, make sure your computer and the printer are on the same network. For example, if you inadvertently connect to your neighbor's password-free network, your printer will not show up. More generally, confirm that your wireless network is functioning properly. To do so, go to the printer's Queue window and select Printer -> Network Diagnostics.
If everything appears OK, make sure the Mac knows that the printer is connected. To do this, launch System Profiler (in /Applications/Utilities) and go to the relevant section for your printer's type of connection. For example, for a USB-connected printer, go to the USB section. If you don't see your printer listed, the problem may be at your Mac's end of the chain. Restart your Mac and check System Profiler again. If the printer still doesn't appear, you may have a hardware problem, such as a defective USB port or a broken printer. To zero in on the cause, try general troubleshooting techniques, such as switching the printer to a different USB port and logging in to a different user account.
When he isn't Twittering (@tedlandau), Macworld Senior Contributor Ted Landau is busy working on the third edition of Take Control of Your iPhone.