Since macOS 10.12 Sierra, Apple dropped support for USB modems on Mac such as the US Robotics modem. Although you can still fax from Sierra and macOS 10.13 High Sierra using an all-in-one printer for Mac that supports faxing, not everyone has one. So here we show you an easy and free way to restore USB modem support to Sierra and High Sierra so that you can still fax from your Mac using a USB modem. Note that if you plan to send faxes from Sierra or High Sierra regularly, we highly recommend reading our guide on how to fax from a Mac which recommends many easier ways to fax from macOS without a modem.

For most people, Apple’s decision to drop USB modem support on Macs is mainly just an annoying frustration but for medical facilities and other businesses that handle customer data, it’s a more serious problem. Medical institutions that use EMR for Mac software for example need to be able to have on site faxing facilities as most third party fax services such as eFax do not comply with strict HIPAA regulations regarding the protection of customer data.

Unfortunately, the fact is there’s no “easy” way to restore USB fax modems support to Sierra and High Sierra but by far the easiest solution is to use the free version of Parallels Desktop Lite to run OS X 10.11 El Capitan alongside Sierra and High Sierra. El Capitan was the last version of OS X to support USB modems and installing it as a secondary OS on your Mac is very easy. There is also a more complicated way to add USB modem support to Sierra and High Sierra but it is very difficult for the average user as not only does it involve using Terminal and disabling SIP security features but it can be very tricky to get working properly. It’s also possible that it will not work with future versions of macOS so the following method is more future proof if you want to use a USB modem on your Mac.

How to Fax From Sierra & High Sierra With a Modem

Before you start this tutorial, you’ll need some kind of external storage device with at least 8GB of storage space on. An external hard drive for Mac but this can be a bit expensive for the job and a cheap USB pen drive costing little more than $10 or an SD card (if your Mac has an SD card slot) will suffice. This will be used to create a bootable version of El Capitan which you can install in Parallels.

If you’ve got this ready, here’s how to fax from Mac Serra & High Sierra with a USB modem.

  1. Download and install Parallels Desktop Lite. This is a basic version of the easy to use Parallels software which is the best way to run Windows on Mac and older versions of OS X such as El Capitan at the same time as Sierra and High Sierra. The great thing is Parallels Desktop Lite is completely free to use – you only have to upgrade to the full version of Parallels if you want to run Windows in it (which we don’t for the purposes of this tutorial).
  2. You then need to download El Capitan onto your Mac. This will download a 6.09GB “Install El Capitan” file to your Applications folder.
  3. You then need to make it bootable from your external drive. The easiest way to to this is to download the free boot utility DiskMakerX. Simply open and install it and it will automatically search your Mac for the El Capitan file you just downloaded and prompt you to use it.fax from mac sierra high sierra - diskmaker x
  4. Click on “Use this copy” and DiskMakerX will then automatically search and locate your attached storage device.  You’ll see a warning message that it will wipe the drive and create the boot disk. Click on “Erase then create the disk”.fax from mac sierra - diskmakerx erase
  5. When the disk is created, open Parallels Desktop Lite. In the setup wizard, select “New Virtual Machine”.fax sierra mac - parallels install os
  6. Parallels will then automatically detect the El Capitan boot drive inserted into your Mac and prompt you to install it.fax mac sierra - el capitan
  7. Once installation of El Capitan in Parallels Lite is complete, you’re done. Simply insert any USB modem into one of your Mac’s USB drives and add it to El Capitan in your Network preferences. You should notice that El Capitan detects it automatically anyway. You can now fax from El Capitan within Sierra or High Sierra anytime you want just like before!fax from high sierra - usb modem

If you have any problems faxing from Sierra or High Sierra using this tutorial, let us know in the comments below or get in touch direct.

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3 Responses

  1. Lednek

    Thanks for supplying this info. Question: Can I use a bootable version of El Capitan located in a separate partition on the hard disk of my iMac (now using High Sierra) to copy to DiskMakerX and then use Parallels? Right now, I have to reboot the iMac any time that I need to use El Capitan to fax a document, and that is not a very convenient way to fax.

  2. Unicorn76

    Fortunately, i was wise enough to keep a partition with Yosemite which I can boot up and fax as needed. Easy way is to pester Apple to make it an optional add on for us faxmodem users.


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