Resolving iTunes Error 17 When Upgrading or Restoring iOS Devices

Mar 22, 2014 - 11 Comments

itunes-icon If you’re attempting to upgrade or restore an iPhone, iPad, iPod touch, or Apple TV by way of iTunes and you encounter an Error 17 alert, you’re probably experiencing an issue with the computer connecting to Apple’s servers. This can be caused by a variety of things and users may see it either when trying to update or restore normally through iTunes, or even when using firmware IPSW retrieved directly from Apple.

If you’re familiar with troubleshooting iTunes error messages, you’ll find that Error 17 is in the same category of problems as Error 3194 and the “device isn’t eligible” build message. Somewhat unique to Error 17, however, is that it more often seems to be triggered with direct internet connectivity issues on a Windows PC, like say a broader wi-fi problem like failed DHCP assignments, or a very restrictive firewall.

Before digging in to the troubleshooting steps, if you’re simply trying to update iOS to the newest version, try using OTA directly on the device itself. This lets you bypass any errors from iTunes completely because you won’t need to use a computer to update the iPhone/iPad/iPod.

Gotta use iTunes for the upgrade or restore for whatever reason? No big deal, let’s get started troubleshooting this error so you can get everything working as intended:

1: Check Internet Connectivity

A connectivity issue is often the most common cause of Error 17. The last time I ran into the problem was due to a PC joining the wrong local router where DHCP was failing, thereby offering no internet access in general. The computer may think it’s online, but it’s not actually able to reach the outside world. Yes, it’s often that simple, thus the first few steps to take are to check that broader internet connectivity with the outside world is functioning as intended.

1A: Double-check the Internet Connection is Active

iTunes must be able to communicate with Apple’s servers in order to restore or install the latest iOS software and verify the build. Be sure that the computer is connected to the internet and able to access the outside world. This is pretty easy, from the computer you want to check just open a web browser and head to,, or another fine website. Note that web access alone does not determine if everything will be in order, because many apps or services may allow web access ports while simultaneously blocking other ports and services. Which leads us to the next step…

1B: Check Firewalls, Proxies, Security Software, and Anti-Virus

You may need to temporarily disable the computers firewall, strict security software, proxies, VPN’s, or antivirus software. Many of these apps and services will block access to outside servers and services which can lead to issues with iOS management through iTunes.

Disabling a firewall and anti-virus apps can vary dramatically depending on what software is installed or in use and thus there’s really no obvious way to provide universally relevant instructions, but if you have something like an aforementioned service in use, temporarily disable it while trying to update/restore an iOS device. You can re-enable these services after you have been successful.

2: Get the Newest Version of iTunes

Some older versions of iTunes are unable to install the latest versions of iOS, or restore the latest version of the iPhone / iPad is newer than that which the installed iTunes version supports, accordingly, you may see the error 17 message.

Mac users can download the latest version by checking  Apple menu > Software Update and the Mac App Store.

Mac users and Windows users can also go to Apple’s iTunes download page and get the latest version directly from there. Install it and try again.

This is necessary if the computer is using an old version of iTunes.

2: Check the Hosts File for Apple Server Entries

The hosts file may have an entry within it blocking access to Apple servers.

Checking Hosts for Windows

If you’re on a Windows machine and encounter Error 17, you can usually resolve it simply by deleting the hosts file and then rebooting. The location of the hosts file in Windows is usually the following, open it in NotePad or whatever your editor of choice is to see if there is any entry with “” contained within:


Note \%WinDir%\ is the Windows system folder found in the root, typically on the C: drive, but your PC setup may vary depending on what version of Windows you’re using and if you get ambitious with customizations. The primary system directory may simply be \Windows\ as well, but the subdirectory containing hosts will always be \System32\Drivers\Etc\ on any Windows XP, Windows Vista, Windows 7, or Windows 8 PC.

If you have made customizations to the hosts document for blocking or domain resolution purposes, you’ll probably want to save a copy of the file before deleting it and rebooting. Or you can edit it with NotePad and delete any entry that has “” alongside it, or comment it out by throwing a # pound sign in front of the entry. It’s generally a good idea to backup the file before doing anything with it so that you can easily revert if necessary.

Checking Hosts under Mac OS X

Mac users can open Terminal and type the following command to dump the contents of hosts onto the screen:

cat /etc/hosts

If you see any entry with “” or “” you need to modify the file to stop the hosts block, or temporarily relocate the hosts file to be able to communicate with their servers. Put a # in front of the entry and save the file for a quick fix. Users who are new to the process can learn more about editing the hosts file on a Mac here.

If you’re still encountering error 17 or similar problems, you may want to try using a different computer on a different outside network to see if that works. Annoying perhaps, but it may indicate that the hosts modification, firewall, or other blockade was not properly addressed. This is particularly worthwhile if you’re trying to restore/update an iPhone when you’re on a strict corporate network, so rather than trying to get the systems administrator to make changes to the firewall restrictions, you’re probably better off simply completing the process when you get home on your normal network.

Leave a comment with what worked for you!


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Posted by: Paul Horowitz in iPad, iPhone, iTunes, Troubleshooting


» Comments RSS Feed

  1. Charles says:

    Hey thanks! Editing the hosts file worked, I was able to restore my device.

  2. Eric says:

    proper method is clear hosts files which item include *

  3. karosan says:

    thanks for guidance. error (17) resolved after emptying host file.

  4. mia says:

    please help me nothing worked with me I’ve been trying for ages now.

  5. Thank you very much for your help.
    People were telling me my phone was dead! But, thanks to you, it survived!

  6. emmz says:

    I have had various error messages when trying to update and ended up in a boot loop i couldnt seem to get out off. Tried everything i could find on net such as recboot and tiny umbrella and in end i simply used a different usb cable in a different slot and hey presto it worked.

  7. Brett Burkhart says:

    Was trying to update my iPhone 6 to the latest iOS 8 on my Windows 7 laptop, kept getting the “Unknown Error (17)” window when updating from iTunes. After deleting the hosts file and rebooting, and then trying again from iTunes….it worked!!! It forced me to FULLY RESTORE (which sucked), but thankfully I backed up my phone before updating the OS. Backup! Backup! Backup!!!

    I’ve had this issue before from my laptop using iTunes, never figured it out, so I’d just update via General Settings on the phone itself. Sounds like I can now use iTunes on my PC without issues. Thanks for the info about deleting the host file!!!

  8. Bill Kennedy says:

    Editing the hosts file worked for me. I was having trouble updating an iPad mini whose Beta software had expired. Once I # out the line in the hosts file, I was able to update to the latest beta.

  9. Alise Cambera says:

    I am facing an error with my iPhone, but it is not Error 17 actually it is Error 28. as you resolve the problem of Error 17 with great words. Please post something about Error 28. The only thing i have got to know about it that this problem is a bad dock connector on the iPhone. Must change the connector. What does that mean?

  10. Low says:

    I was glad to see this article because it just happened that the last week I was trying to update my device and was failing with 3194 error. Unfortunately, however, this article does not provide anything new that you can already discover via searching.

    I have tried the manual update from a PC and a Mac. Both was failing. My connections are fine. I have a 15/5 connection and measuring the speed is spot on both using wireless or wired connections.

    My original Fios router I got from Verizon never had an issue and still working fine (knock on wood). However, I don’t know much in general about networking so I don’t touch things like DHCP and port forwarding and changing/setting up IPs and alike. I have everything the way Verizon set it up and it works ever since.

    As I was saying, the install fails both on a PC (using wired) and from a new Mac (using wireless).

    I did check in the router control panel though a while back, and I saw a LOT (…and I mean A LOT) of port forward settings related to “Toredo”.

    I did search on the word, but since I’m not a networking person I wasn’t sure what all those bunch of entries were. I know I didn’t add them, that’s for sure. I did built new PC in the past few years, and some I did a clean install a few times, so I’m not sure if those entries are somehow being automatically created when a “new” PC or Mac is registered. I am not a gamer and I don’t have any consoles that would’ve needed or created those entries. Since I’m not sure why they are there or what they are used for, I did not delete them (and as I was saying there’s a lot of Toredo entries – I guess they are accumulated in the past 6 or so years since I got the router.)

    The hosts files are all fine.

    So at this point I’m suspicious about those Toredo entries in the router because otherwise I don’t see any reason why I would keep getting the error.

    So I just did an OTA update.

    • Paco says:

      So long story short, your restrictive router/firewall is causing the problem, which is addressed specifically in this article. Ok.

      I’m sure that will be helpful to someone else.

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