What is an unknown error occurred (1667)

While trying to update, restore or sync iPhone, iPad, or other iOS devices some users get unlucky to enter a 1667 error that prevents it. The message that intervenes in the updating/restoration process usually appears as a pop-up window and states the following:

“There was a problem downloading the software for the iPhone. An unknown error occurred (1667).”

The most common causes of this and other similar issues (e.g., errors 53, 14, 10, 2015, 1110, 3194, 2005, 2003, etc.) are badly connected or damaged USB cables, outdated software, insufficient space, compatibility issues, internet connection, and other possible issues as well. In this guide, we have gathered a number of easy-to-perform solutions that will help you potentially address the 1667 error and finally restore or update your device.

itunes unknown error occurred 1667

Download repair tool

Sometimes fixing errors can be beyond our capabilities and available options. This is where third-party tools come in handy and relieve these difficulties and limitations. If you encounter error 1667 or similar issues and are unable to resolve them using our manual methods below, consider using Tenorshare ReiBoot – a great recovery tool designed to handle errors like that. Learn how to use it to resolve the errors and successfully restore or update an IOS device here below.

Download iOS Repair Tool
  1. Download and install ReiBoot for either Mac or Windows.
  2. Once done, open the app and plug your device into the computer.
  3. The program should recognize your device and offer a couple of options.
  4. Choose Standard if you simply want to update your device or Deep repair if you want to fully restore it.
  5. Then, download the firmware found by the app for your smartphone by clicking Download.
  6. Once the process is finished, click Repair now to start resolving the problems.
  7. Standard is meant to search for basic issues and bugs to address them without wiping out your data.

    Deep repair will reset your device to factory settings and delete the entire data stored on it.

  8. Wait until the app finishes its repair and restores your device. It will take about 15 minutes to end.

If your device is stuck on the Apple logo and does not want to move any further, skip over to these steps and get to the original sequence of methods after reviving your device.

1. Check your USB cable

We advise you to begin by verifying the functionality of your USB cable. You should make sure it is firmly connected to both your Mac (or Windows) and IOS device. You can also try other ports to see if anything changes. Using another USB cable as a substitute is also an option to try. If the error still persists despite everything seems to be okay, proceed to explore the other solutions provided below.

2. Make sure you have free memory on your iPhone

It is likely that the update process will fail if there is not enough free space available. Keep in mind that the update needs space to be downloaded and installed eventually. If there is not enough free memory on a device for the necessary update, then it is more likely to encounter a problem like error 1667. To prevent this, make sure that your iPhone (or other IOS device) has a minimum of a few gigabytes of internal storage available. You can do this by checking the device’s storage settings like written below:

  1. Go to Settings and navigate to General.
  2. Then find and choose [Device] Storage.

How much space is already occupied and how much is free will be visible there. If there is not a lot of it left and you see barely any free space, then this can be the reason why you are subject to facing the error. Empty some space by deleting or transferring unnecessary files to another storage.

3. Ensure your iTunes and macOS are up-to-date

Maintaining an up-to-date system is crucial for stability and smooth operation. When encountering issues while updating or restoring an iOS device through iTunes, many users have found success in solving the problem by installing the latest software updates. This is why we recommend you check to check both iTunes and macOS for available updates and install them if any are found. Here is a brief instruction on how you can do this:

To install updates for macOS:

  1. Go to Apple menu in the top left corner of your screen and choose System Preferences.
  2. Then, click Software update and choose Update Now to install the latest update available for your current version.
  3. If you don’t see this button, this means your system is already up-to-date.

Usually, other apps like iTunes get updated along with installing the latest macOS version. Despite this, it is still worth double-checking.

To install updates for iTunes:

  1. Open App Store from the dock on your screen.
  2. Move to Updates on top of the window or left pane and search for iTunes from the list.
  3. If there are any updates available, you will be able to click on Install to get them.

Otherwise, your iTunes service is up-to-date. If you installed iTunes on Windows from Microsoft Store, do a similar procedure there.

4. Force-restart your device

This method is designed to help users get out of the Apple logo loop which may occur while updating their device through iTunes. This is quite a common issue that happens during the update. Here is what you can do to get out of this black hole and try updating your device using alternative methods again.

iPhone 8 or later:

  1. Press and quickly release the Volume Up button.
  2. Press and quickly release the Volume Down button.
  3. Press and hold the Side button (which you use to unlock your screen) until you see the Apple logo.

iPhone 7, iPhone 7 Plus, and iPod touch (7th generation):

  1. Press and hold the Side (or Top) button and the Volume Down button together at the same time.
  2. Likewise in the previous steps, the Apple logo should appear on the screen.

iPad models with a Home button, iPhone 6s or earlier, and iPod touch (6th generation) or earlier:

  1. Press and hold both the Side (or Top) button and the Home button until you see the same Apple logo as it was above.

iPad models without a Home button:

  1. Press and quickly release the Volume Up button.
  2. Press and quickly release the Volume Down button.
  3. Then press-hold the Power button and wait until the iPad restarts.

Basically, the pattern of restarting your device is the same only varying by a combination of buttons on different generations of IOS devices.

5. Disable third-party security software/Try to solve Internet problems

Sometimes third-party security software may obstruct access to crucial packages that need to be retrieved from Apple servers. This, therefore, causes communication issues with Apple servers and may lead to error codes like 1667. Let’s do the following to make sure it is not the case anymore:

  1. Try to disable your third-party antivirus or other security software.
  2. If this does not help or there is simply no third-party software you can disable, maybe the problem is with your Internet connection.

  3. Restart the router plus computer and reconnect to your wireless network again.
  4. If you are using a wireless Internet connection, try to connect an Ethernet cable directly to your computer (if there is one available). This could also help you resolve the problem.
  5. You can also find another network and try to use it instead.

6. Configure your hosts file

Whether it is a Mac or Windows, host files are used to store information that facilitates prover server connections. If any entries are altered from their default values, it may cause certain problems with the server connection. To determine if this is the case, do the following steps:

for Windows users:

Instructions for Windows may vary depending on which version is currently installed. This is why we recommend you visit this page and choose instructions dedicated to your Windows OS.

for Mac users:

  1. Go to Applications & Utilities using Finder.
  2. Open Terminal and type this command sudo nano /private/etc/hosts. Press Return.
  3. If asked, enter the password you use to log into the system.
  4. After seeing a window full of different entries, navigate to gs.apple.com using arrow keys on your keyboard.
  5. Note! If there is no entry named gs.apple.com inside of the window, this means the “hosts” file has nothing to do with the error. Simply ignore this method and skip further to others below.

  6. Add the # symbol and a space (“# “) to the beginning of the gs.apple.com entry.
  7. Press Control-O to save the file and press Return when asked to type the filename.
  8. After that, press Control-X to exit the window and restart your Mac at the end.
  9. Once all of these steps are done, attempt to update or restore your iOS device again. We hope it helps.

7. Update or Restore your iPhone through Settings

If there is no specific reason why you want to update your device exactly through iTunes, then you can also do it via Settings on iPhone itself. This is an alternative method if attempts to resolve the issue with iTunes do not lead to any success. You can check the availability of new updates for your device and learn how to restore it by following the steps below:

To update your iPhone through settings:

  1. Open Settings and navigate to General.
  2. From there, find and open Software Update.
  3. If any new updates are pending, you will be able to click on Download and Install.

To restore your iPhone through settings:

  1. Open Settings and navigate to General.
  2. From there, go to Transfer or Reset iPhone and Reset sections.
  3. Choose which reset option you need and do so.

8. Try using another computer

If none of the methods above helped you figure things out with error 1667, consider borrowing a Mac or Windows PC from your friend or other family members to update/restore the problematic device. This approach may be worth trying as the problem could be with the computer itself. Additionally, It is also possible your USB port is damaged as mentioned above, which may not be evident without proper expertise. Therefore, give it a try using someone else’s computer or laptop.


“An unknown error occurred (1667)” is not the only error that may appear when updating or restoring an iOS device through iTunes. Many other similar issues have related causes, and the solutions outlined above in this guide can likely be used to resolve them as well if you encounter some other similar problem in the future. We hope this article has been helpful and let you successfully update or restore your device using iTunes.

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