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Reinstall USB Fax Modem Capabilities on macOS Sierra

macOS Sierra USB Fax Modem Reinstallation

This post tells how to reinstall USB fax modem capabilities on macOS Sierra, after Apple dropped support.

If dropping support for fax modems affects you negatively, please take the time to issue feedback at Apple's website.

To restore USB Fax Modem capability to Sierra, simply copy the files listed below from your old El Capitan install.

Here is this list of files you need:

/Library/Printers/Fax.ppd # copy /System/Library/Frameworks/.../Fax.ppd file to /Library/Printers
/System/Library/CoreServices/Menu extras/

Here are the basic steps. I confirm that this works for me:

  • This requires a Time Machine, Disk Utility, Carbon Copy Cloner, or other backup of your pre-Sierra image.
  • Reboot your Mac with the Command-R recovery partition, and, if necessary (it should be if it's not), use Disk Utility to unlock and mount your encrypted boot drive.
  • Open the Terminal, and disable SIP using the command csrutil disable.
  • Reboot the Mac normally.
  • Use cp -R or rsync to copy over all the files to your Sierra boot drive. Ensure that the files have no ACL's or extended attributes if necessary with chmod -N and xargs -c. Test with ls -e and xargs.
  • Reboot your Mac with the Command-R recovery partition, and, if necessary (it should be if it's not), use Disk Utility to unlock and mount your encrypted boot drive.
  • Open the Terminal, and enable SIP using the command csrutil enable. Do not ignore this step.
  • Reboot the Mac normally.
  • Open the Directory Utility app from the Spotlight search tool, unlock with admin credentials, and enable the root account.
  • In Safari, browse to your Mac's CUPS server at http://localhost:631, Administration>Add Printer, authenticate as root and follow the steps to add the printer with a URI that looks like fax://dev/cu.usbmodem9804243. This will be the same printer in the previous plist prefs file, /Library/Preferences/ Specify the PPD file /Library/Printers/Fax.ppd.
  • You should now see a working USB Fax Modem in System Preferences>Printers & Scanners.
  • Open the Directory Utility app from the Spotlight search tool, unlock with admin credentials, and disable the root account.
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semitech commented Feb 3, 2017

This is sorely needed: medical offices still REQUIRE communication via FAX because of HIPAA regulations. My US Robotics 5637 for my MacBook would be useless under Mac OS 10.12, Sierra, without FAX modem support.
However, I'm not quite the Unix expert that the author is. I know enough Unix to execute a script. Any chance somebody can write these steps into a Unix executable?

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essandess commented Feb 8, 2017

Scripting will not help here because the steps involve temporarily disabling SIP to restore original files to SIP-protected directories.

Beyond DIY, your best bet is to send feedback to Apple (link above), and ask them politely to fix the problem they created.

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Jollyjul commented Jun 15, 2017

I am having some problems following these instructions.
Disabling SIP seems to need the command csrutil, and not scrutil.
xargs -c does not appear to be a valid option.
I can manage to use the CUPS server, but when I look at the FaxPrefs.plist file, I do not see anything that looks like the example name you have given, cu.usbmodem9804243. Where do I find that name? Also, since fax:: is not one of the choices, I am using http:: Is that correct?

Bottom line, I can't get this to recognize my USR USB modem.

Any help would be most appreciated.

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memushy commented Jun 19, 2017

Fresh installation of Mac OS Sierra 10.12.5
Reboot in recovery mode and Disable SIP
Reboot in normal mode and manually copied listed files (from working El Capitan installation)
Reboot in recovery mode and Enable SIP
Reboot in normal mode and Enable root
Open Safari and open http://localhost:631 but web interface was disabled
Used terminal command cupsctl WebInterface=yes to enable web interface
Re-open Safari and open http://localhost:631 and authenticated as root
Click into Administration and add printer but there is no usb fax

It is listed in the /Library/Preferences/ file
along the lines of fax://dev/cu.usbmodem9804243

Any help appriciated as to why it is not showing up.

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memushy commented Jun 23, 2017

Didn't manage to get the usb fax modem working directly in Sierra, however...

I installed parallels desktop lite (free in app store for OS X installations) and seemed easier than virtualbox
Installed El Capitan from the El Capitan install app (10.11.6)
Plugged in USB modem with the virtual El Capitan open and it recognised the device
Added the modem in printers, setup its prefs and all seems to be working ok.

Hopefully this may help others.

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memillerlmft commented Jul 10, 2017

I also would appreciate hearing from somebody who has been able to make this process work. I am profoundly ignorant (I NEVER touch Terminal, cuz I am aware of my level of incompetence), and am reluctant to proceed. However, I really want to restore my good old computer-as-fax-machine capability! (Yes, I put in a request at the Apple Feedback site, but I have no illusions about Apple reinstating the function. We're on our own, apparently.)
GVCCbob, I have the same fantasy of copying the listed files over from an older El Capitan device (I did find them, at least), but your comments make me doubt it would be that simple. I hope you keep trying, and share what you learn with the rest of us.

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GVCCbob commented Jul 17, 2017

Victory, for those following the thread I was able to get the Fax USB modem working in Sierra after about 10 hours of fooling around with it. I was able to get a selectable Modem connection in CUPS that seemed to allow the connection. Also I think the permissions is important so I matched the permissions of all transferred files. However, no receive options so you can not receive a fax. It is missing in the Preferences pane. Tried to dial the fax number and no connection just ringing.

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GVCCbob commented Jul 17, 2017

So this is good that you can fax, but where are the files for receiving faxes on the mac. They will need to be transferred also otherwise you have 1/2 of a fax machine.

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GVCCbob commented Jul 17, 2017

What happened to the Receive Options? I can no longer receive faxes, line just rings does not connect.

screen shot 2017-07-17 at 1 33 24 pm

What file am I missing? Or what do I have set wrong. Modem is connected and working.


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GVCCbob commented Aug 4, 2017

Has anyone come up with a fix to bring the Receive Fax Option into the Print Fax Window???

Print fax works great but no one can send a fax to a Sierra Mac OS via the USB Modem!


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subjectivity commented Aug 8, 2017

Re: landline fax directly from document on Apple computer that has Sierra (using no fax machines, using no online faxing, just direct computer, landline faxing, no Internet), is it possible to attach a powered usb modem to iMac/Sierra 10.12.6, and to landline (this hardware stuff seems obviously easy and possible), and is there software (3rd party) that would be accepted by Sierra for sending and receiving faxes, and for keeping a fax database? (Similar to the way WFS (Windows Fax and Scan) does in W7Pro on pc's). Apple refuses to answer. Says it requires asking 3rd party modem companies if they have such software; Apple said it comes down to software. Does anyone know, is this correct, it's a matter of getting software that Sierra will accept? and is there any such software? In the instructions given above, I did not follow, not certain I'd trust myself to do it right, and not sure if you meant to copy those files from another Apple computer (I have a laptop that has Mavericks, not El Capitain) and paste them to the iMac/Sierra?

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GVCCbob commented Aug 9, 2017

The good news is swapping out the the Sierra PrintAndScan.prefPane file with the PrintAndScan.prefPane file from Maverick or El Capitan gets back the Receive Options into the Print and Scan Window.

The not so good news is it does not do anything.

I have no idea what files that option links to or where those files are.

Ideas anyone?

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mikejrh commented Sep 28, 2017

I needed to reinstall USB fax modem capabilities after upgrading to High Sierra; I had fax modem capability with Sierra using these instructions; however I now get "holding for Authentication" in the fax window after submitting a job. Any ideas ?

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