Duplicate printers adding to printer list after printing

OK, I've done some investigating and think I know what is going on, though I am still at a loss on how to prevent it.

I have Printer Sharing turned on, so that the printers that I have physically connected to my local computer can be used by Parallels with Bonjour for Windows. The reason for this is that I have had trouble installing my printers in Windows under Parallels.

When Printer Sharing is off, there is no problem. The Mac does not assign any host name to the printers.

When Printer Sharing is on, then the host for the local printers will change. At first it will be a "xxx.local" name, which seems most appropriate. Now, I use two different wireless networks, one at my office and one at home. When I bring my Mac, say, from my office (where my printers are) to my home and reboot it, then it will assign the printers to a "xxx.lan" host, where "xxx" is the Mac's network name. (I guess this is so printer sharing can let the printers be shared on the network?)

If I then bring the Mac back to my office without rebooting (just sleeping), and the Mac connects to a different wireless network, it will not recognize that the printers are the same as before and add duplicates labled "<printername>-1".

So I will pose the question, of whether anyone knows why this occurs, or whether I can force the printers to stay local even if they are shared?

I have the same problem, except in a different circumstance. I use my MacBook Pro at my office and at home. When move my MacBook back to my office, and plug in the printers while the Mac is in sleep or sometimes on, it will add duplicate printers, also with the "-1" suffix. My printers are a Brother MFC-7420, HP Deskjet 6980 and a Dymo LabelWriter Duo. All printers are duplicated.

MacBookPro Core 2 Duo 15" Mac OS X (10.4.8)

The -1 suffix will occur when another instance of the same printer using the same connection is added to the Printer List. As to why this happens to you and the original postee is interesting.

I have seen this occur after adding a printer manually, only to find that on returning to the Printer List, the manual added version is the second instance (-1) because the software for the printer has found it automatically.

Do you have the same printers at home as you do at work? Or is it just the work printers that get found again?

Also, do you make use of the 'location' function for home vs work?

Hi,
--Go to applications>>utilites and open printer setup utility.
--Now next to the blue apple which is at the top left corner you have printer setup utility menu
--Click on that so it will reset the printing system.
--Restart the computer and re-add the printer.

lets c whether this resolves the problem.

To answer PAHU first, I have a HP Deskjet at home but it is a different model (5850). Anyway, the problem occurs reguardless of whether I hook up my home printer or not. I do not use locations, everything is set to automatic, I thought locations was only network-related (all my printers are hooked up via USB).

Ranjeeth, I have reset my printing system several times, both to try to solve this as well as various driver problems. So this does not help.

Yes, locations are typically used for changing network preferences. I just made an assumption that you connect to all 3 printers simultaneously, like on a network, but I guess you only connect one or two via USB when you need to print.

Do you get more than one duplication, such as -2, or is it only ever the one additional copy for each printer?

Can you also tell us if you have had to install software to add all of the office printers or are they included with OS X?

I have in one case gotten a double duplication ("-2") before reseting the printing system to fix it.

I connect all 3 printer via USB , one directly (the Brother) and the other two on a hub.

I needed to install software for the Dymo LaberWriter Duo driver. For the Brother MFC-7820 and HP 6980 I have installed some additional software (scanner driver and printer utility, respectively), but kept the original OSX drivers. In any case, the problem arose before I installed these software, at least in the case of the HP.

Does the Brother and the HP have card slots. I've seen AIO's with support for CF cards, etc, appear more than once in the printer list. Also, if the devices support faxing then I have also seen two instances of the same device in the list.

You're right, it doesn't explain why the HP appears twice. You said that it happens when the Mac is in sleep or on. Does it occur if you connect the printers first and then turn on the Mac?

My last thoughts for the night (it's 11.30pm here) is that the Mac must not think that the printer is already installed. When the second instance appears, I would check the CUPS printer web page ( http://127.0.0.1:631/printers) to see if both printers have the same setup. You could also check System Profiler to see what is shown under Hardware > Printers and Hardware > USB.

Interesting, I didn't know about the CUPS administration URL.

I investigated this, and found something odd. The printer names had links that led to nowhere, in fact a lan name in common with my old PC (which is not networked to the Mac) so this seemed odd.

I looked then at Printer Setup (Name & Location) in the Control Panel and discovered that the host name for all my printers was also set to this strange lan address.

I then tried to restart the Mac, and now the host name is blank as I suppose it should be. And unplugging and replugging the printers in the USB port now does not create duplicates.

So I suppose that on occasion my Mac gives my printers a wrong address and that this causes some internal confusion. I have printer sharing on, in order for the printers to work with Parallels, perhaps this is a factor?

My guess is now that the Mac wirelessly connects to a peer-to-peer network to my old PC when I bring it home. I created a network like this a long time ago when I got my Mac in order to wirelessly transfer files. I thought I had gotten rid of it. Any thoughts on how to remedy this situation, if my guess indeed is correct? (It would explain why this only happens after I bring my Mac home and then back to my office again.)

If you had previously had your printers shared by the old PC and had added them to the Mac, then I could understand why the printer would reappear in the printer list when you reconnected to the network. But if you never had the printers shared from the PC or had added them if/when they were shared, then I don't see why they would be reappearing when you connect. So I wonder if Parallels could be the cause? Are you sure you need to set the printers as shared for Parallels to be able to use them.

If it's not Parallels, then a reset printing system should remove these networked unwanted printers, as the file printers.conf (located in etc/cups) which keeps the listing of added printers will be reset.

No card slots but the Brother is a multifunction machine with fax and scanner. That doesn't explain the HP, though.