iMac Can't Connect to Printer

Hi,

USB in "I have been printing from my old workhorse HP LaserJet 4000TN for years which is connected directly to my late 2012 iMac with a USB cable." in your original post is probably just a typographical error, but do you have access to a USB-to-parallel adapter? If so, you may want to check whether it is possible to print from the computer's USB port to the parallel port of the printer. If successful, this could possibly indicate a problem with the Ethernet connection and the print server.

Also, what about printer drivers? You mentioned "LaserJet 4000 series software". Is this software still available/accessible? If necessary, if not automatically downloaded/installed, you could perhaps try the HP 5.1.1 Printer Software Update from Apple (the system requirements say macOS 10.14; it may or may not work with macOS 10.12 Sierra). An HP LaserJet 4000 Series driver (19.13) is mentioned in Printer and scanner drivers for Mac - Apple Support.

When attempting to add a network printer by its IP address, any change if you choose to use generic postscript or PCL printer software?

http://h10032.www1.hp.com/ctg/Manual/bpl03783.pdf

http://h10032.www1.hp.com/ctg/Manual/bpl03781.pdf

http://h10032.www1.hp.com/ctg/Manual/bpl05328.pdf

Thanks, please try restarting in Safe Mode per the instructions below:

Please restart the computer in Safe Mode per the directions in the  How to use safe mode on your Mac - Apple Support link.

Note: If you are using a wireless keyboard please either plug it in using the supplied Lightning cable that shipped with it. If you are using a legacy keyboard or a third-party keyboard that does not have re-charging abilities, please use any USB keyboard. Also note that a Safe Mode restart may require you to hold down the shift key for up to 5 minutes before the computer starts in Safe Mode. You will know it is in Safe Mode when you see “Safe Mode” in the upper right of the display.

Next, please restart normally and please retest.

Finally, by chance is there any third party antivirus, cleaning or ANY other third party maintenance apps installed on the device?

Let's try the following to look for anything obvious we are missing:

It will help us get a good idea of what is causing your problem if you provide a report of your system, that way we do not have to play 20 questions with you. The report we are requesting does NOT provide any personal information and is extremely safe to use. Please navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it.

When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again.

For instructions on how to download your EtreCheck report and attach it to your reply to this message please click How to use the Add Text Feature When Post… - Apple Community

Please use Reset Printing System feature and then Adding a printer.

Well there are some serious issues, first is someone went in and modified Mac OS. This could be why you cannot connect to the printer. It is a simple fix though, you have to install Mac OS, this type of install does not affect your data at all, it simply installs the missing pieces of Mac OS. That being said, please ensure your backup is working okay before installing just as an insurance policy.

Please restart in the Recovery Partition by holding down Command + R on startup and you will see where to install Mac OS.

Also, your machine is starved for RAM. You never upgraded the RAM and it only has 50MB left, that is WAY too low. I would recommend adding another 8-16GB of either Crucial.com or Macsales.com RAM. Why these vendors....because iMacs are very sensitive to using quality RAM and both vendors supply very high quality products at very competitive prices, have lifetime warranties on RAM and provide excellent service. In short, there is no reason not to use one of them.

Please complete the install first, then attempt to install your printer and see how it goes.

Your security updates are still disabled which sounds normal due to the age of Sierra however this might be your problem, I am surprised that installing Mac OS did not solve that. I would recommend that you give AppleCare a call, explain to them.

• What the problem is, cannot print to legacy printer using IP address method. Note the connection type you are using (have you tried another Ethernet cable by chance??)
• Let them know you have reset the printing system already.
• That you recently installed Mac OS from the Recovery partition.

Exactly what did you try several times with no luck? Please be specific. Resetting the Printer System is NOT the same as deleting a printer.

If your wireless keyboard is rechargeable it will have a port on it to plug a Lightning cable into it, plug the other end into your Mac to charge the keyboard.