How to fix an unknown error occurred (4037) − iPhone, iPad, iPod touch (iPhone)

Believe it or not, another reason for the "an unknown error occurred (4037)" error message are incorrect date and time settings. Ensure that you set the correct time and date on your computer and mobile device, and then reconnect your device to the computer.

Feel free to check the don't know how to set the time and date guide, if you are not to show how to set them.

Firewall and antivirus settings can be responsible for the "An unknown error occurred (4037)" error message, because they may consider iTunes or your iOS device a threat. To check this, try disabling them temporarily, reconnect your device and check if you still get the error message.

If the error message didn't appear, access the firewall and the antivirus settings and see how they are configured. If you are not sure how to access them, you can check your operating system's or antivirus's help files, or visit the antivirus developer's website.

To disable the Windows Firewall:

To enable the Windows Firewall:

Maybe the error code 4037 appears because the iTunes version installed in your computer is outdated. You always need to update iTunes when a newer version is available, either via iTunes itself or by downloading it from Apple's website, as a way to prevent possible issues.

To check for updates and update iTunes manually, follow the steps below:

1. Open the iTunes app;
2. Click on Help and select Check for updates.
   
   

The operating system is much more complex than it seems. So many tasks and processes are being run in the background even for the tasks that seem simple to us. It is possible that your computer or iOS device are temporary blocked, possibly by a software that has suddenly become unresponsive and interfered with some processes of the operating system, or by a system process that is running in the background.

In this case, to fix this iTunes error, restart the computer and the iOS device and then reconnect your device to the computer.

The hosts file enables you to add URLs of webpages you want to block, which will automatically be blocked in every single browser installed in your computer. Unfortunately, some viruses can modify the hosts file in order to prevent you from downloading an antivirus software, or an update to it, which can find and remove the virus.
 
All you have to do to fix this issue is to open and modify the hosts file, only by removing entries that contain the terms apple or itunes, but proceed with caution, to avoid corrupting the file.

To find and modify the hosts file on a Windows computer:

1. Go to My Computer/This PC and click on Local Disk (C:);
2. Click on Windows and then click on System32;
3. Click on drivers and then on etc.
4. Find and open the hosts file with Notepad (right-click the hosts file -> Open with -> select Notepad).
   
   

To find and modify the hosts file on a Mac OS computer:

1.  Open the Terminal.app by going into Applications -> Utilities -> Terminal.
2. Type the following line: sudo nano /private/etc/hosts (type your username and password when asked)
3. Remove entries associated with apple, or itunes, hold Control + O to save the changes and Control + X to exit
4. Flush the DNS cache by entering the following line (depending on your OS version):
   
   
   • dscacheutil -flushcache - Mac OS X Snow Leopard (v10.6 through v10.6.8)
     
     
   • sudo killall -HUP mDNSResponder - Mac OS X Mavericks, Mountain Lion, and Lion (v10.9.5 and earlier)
     
     
   • sudo discoveryutil mdnsflushcache - Mac OS X Yosemite and later (v10.10 through v10.10.3)
     
     
   • sudo killall -HUP mDNSResponder - Mac OS X Yosemite and later (v10.10.4 or later)

Maybe that the USB port where you plugged in the USB lightning cable is broken, which obstructs the connection between the computer and the iOS device. In order for a connection to be established, the gold plates of the lightning cable needs to touch the gold plates of both the computer's USB port, and the iOS device's lightning port. Plug the USB cable into a different USB port on the computer and try again.

Note: If you use a desktop computer, consider plugging in the USB cable in one of the USB ports on the back side of your computer, which are part of the motherboard, because it is possible the front USB ports are disabled in BIOS, or the link between them and the motherboard is unstable.

Stable Internet access is a prerequisite for almost all operations you do with your iOS device (file syncing, updating, restoring, etc.). Unstable Internet connection may result in incorrectly downloaded (corrupted) files, and errors like 4037.

Verify that your Internet connection is reliable and fast, before performing any action with your iOS device, as iTunes needs to download files from the Internet first.

You may test your Internet connection, and its speed with many online tools, including speedtest.net

Aside from new features, updating your computer's operating system frequently, as soon as an update is available, means that you will receive the latest security updates, and resolve all the bugs or compatibility issues discovered in the previous version of the operating system. Additionally, all the corrupt system files will be fixed with the update. Maybe one of those issues was causing this iTunes error.

Updates are installed automatically, however, it's best to check for updates, and install them, manually. If one is available, install it, and try connecting your computer and iOS device again.

To learn how to update the operating system, check out the how to update my device's operating system guide.

A very overlooked reason for connectivity issues is dirt. Dirt can find its way everywhere, including the device's USB ports. Also, dirt, in any form, can prevent a stable data transfer, which can result in corrupted, incomplete files, as well as error messages, with "an unknown error occurred (4037)" being one of them. It's possible that your computer's USB port or iOS device's lightning port (or both) are dirty.

If this is the case, all you need to do is to grab a cotton swab, sip a small amount of rubbing alcohol on it and then gently clean the USB and lightning ports. Wait until the alcohol evaporates (up to a minute) and then reconnect your devices.

Contacting Apple's support team is the way to go, if you aren't tech-savvy enough and wouldn't try fixing this error by yourself. They will help you diagnose and address the issue. All you would need to tell them is the name of the error.

You can contact Apple's support staff online, any time, via getsupport.apple.com