Getting Down to Business

Replace the Mac OS X 10.1.x LPRIOM.plugin file with that from 10.04

File Needed! In this step, you’ll need to download balthisarfiles.sit and then unstuff it in a location that’s known and accessible to you. You’ll be using it very shortly, below.

Mac OS X depends on a file called LPRIOM.plugin in order for LPR printing to work. It’s located at: /System/Library/Printers/IOMs/

It’s been determined that the upgrade from Mac OS X 10.04 to 10.1 (and subsequently 10.1.1 through 10.1.5) has replaced this file with a newer version that doesn’t allow LPD printing to work properly. Hence, our first goal is to replace this file with an older version “rescued” from Mac OS X 10.04. Note: this file is actually a Mac OS X “package,” so it will appear as a directory in the terminal, and must be treated as such.

Note: keep a backup of this original file somewhere. Since the previous versions of this guide was put out, Apple has released updates that puts Mac OS X at 10.1.5. These recent updates still breaks proper LPR operation, and you’ll need to revert back to this 10.04 version again any time Apple keeps shipping a faulty file. Whenever you perform an OS upgrade in the future, and printing stops working, try replacing this file again.

Note: it’s possible to skip this step. Check out localhost printing in this guide. I do recommend replacing the LPRIOM.plugin until you have your printer up and running – it’s one less thing to go wrong when troubleshooting. Then, when you know things work, you can revert to the original LPRIOM.plugin and use localhost printing.

To perform the surgical replacement, open a terminal window, and su to root, then type the following:

cd /System/Library/Printers/IOMs
…puts you in the correct directory.
mv LPRIOM.plugin ~/originalLPRIOM.plugin
…moves and renames the 10.1 file so we can keep it as a backup. Using the ~/ syntax means it will go to your home directory, but it’s your backup; put it where you want. If you simply rename it in place, your Print Center will have two “LPR Printers Using IP” in the Add Printer options, which is not what we want.
cp -R
…to copy the file, where …path… designates the complete directory path to wherever you unpacked the file.

Note: you need to know the path to the file you’re copying. For example, had I unstuffed it in my own “Downloads” folder, the …path… I would use would be ~jderry/Downloads/balthisarfiles/LPRIOM.

That’s it. You will now be using the old and not-improved version of the LPRIOM.plugin file. You may want to restart the computer, just to make sure the OS knows about the change. Better safe than sorry, right?