Duo Two-Step Authentication: Changing Smartphone Devices


If your organization or business uses Duo two-step authentication, you have likely setup a smartphone with the Duo software. This page describes how to switch to a new phone after you’ve discarded, sold, lost, or traded in an older phone.

Before Adding Your New Device

Because you no longer have access to the phone that was previously setup for Duo access, you won’t be able to login as you have in the past to setup a new Duo device.

However, when you go to login, usually there’s an option to authenticate via a phone call. If you’ve setup a new phone with your same phone number, then you can authenticate and login that way.

Once you login, you’ll see your old device listed as the primary/default device. There won’t be an option to delete it.

You’ll likely, intuitively, attempt to add an additional device. However, this won’t work because your new device has the same phone number as your old device, so the system will generate an error when you try to add it again under the same phone number.

You might think that you could setup the Duo app on your replacement phone, but that won’t be possible because once a device is setup, there doesn’t seem to be a way to generate the barcode to setup the software again.

There may be a link stating, “I need to reset/replace this device.” However, if that link isn’t present under your old smartphone description, you’ll need to follow these additional steps to replace it.

To Delete Your Old Device

What you’ll need to do is add an additional authentication method such as ‘phone call’ to a phone you have access to, and set it as the default device.

Then, and only then, will you be able to remove your old device by clicking on its description link, and then pressing the Delete Device button.

At this point you can follow the steps below to add your new device.

Add Your New Device

  1. At this point, you can choose the ‘Add additional device’ option to add the new replacement smartphone.
  2. Provide the phone number, preferred authentication method (the Duo app), and a description.
  3. Continue to view the barcode.
  4. Start the Duo software on your smartphone.
  5. Choose Add Account.
  6. Scan the barcode displayed on your computer screen.
  7. Test the Duo authentication.
  8. Approve the test login request on your smartphone.
  9. You should get a message on your computer stating the test was successful. Close that window.
  10. You’ll see your list of devices.
  11. Click the description link for your new smartphone. Choose to make it the Default.
  12. If you used a telephone number temporarily as a default device as described above,  you can remove it now. Click on the description link and press the Delete Device button.