How to Update iPhone via iTunes — Step-by-Step Guide

Introduction / Why This Is Needed

Updating an iPhone via iTunes is a reliable alternative method to install a new iOS version, especially if an over-the-air (OTA) update is unavailable due to insufficient device storage or Wi-Fi issues. iTunes allows you to download the firmware directly to your computer and then install it on your iPhone, giving you more control over the process. After following this guide, your iPhone will run the latest iOS version with new features and security patches.

Requirements / Preparation

Before you begin, ensure the following conditions are met:

• iPhone: Compatible with the latest iOS version (typically iPhone 5s and newer), battery charge at least 50%, 5-7 GB of free space.
• Computer:
  • Windows: Windows 10 or 11, with the latest version of iTunes installed (download from Apple's official website).
  • macOS:
    • For macOS Mojave (10.14) and older — install iTunes.
    • For macOS Catalina (10.15) and newer — updates are done via Finder (iTunes is not available). The instructions below apply with minor differences (use Finder instead of iTunes).
• Cable: Original Apple or certified Lightning/USB-C cable.
• Internet: Stable connection for downloading the firmware (file size can reach 5-6 GB).
• Backup: Create one in iTunes/Finder before updating (we will cover this step in detail).

💡 Tip: If a passcode is enabled on your iPhone, make sure you remember it. You may need to enter it to unlock the device after the update.

Step 1: Connect iPhone to Computer and Trust

1. Launch iTunes on your computer (or Finder on macOS Catalina+).
2. Connect your iPhone to the computer using the cable.
3. A prompt "Trust This Computer?" will appear on your iPhone screen. Tap "Trust" and, if prompted, enter your passcode.
4. In iTunes (or Finder), your iPhone's icon will appear in the upper-left corner. Click it to access device management.

⚠️ Important: If iTunes does not detect your iPhone:

• Check the cable and USB port (try a different port or cable).
• Restart both your iPhone and computer.
• On your iPhone, go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings (this will not delete data).
• Ensure all Windows/macOS updates are installed on your computer.

Step 2: Create a Backup in iTunes/Finder

Always create a backup before updating. This protects your data in case of a failure.

1. In the iPhone management section of iTunes (or Finder), go to the "Backups" tab.
2. Choose a backup location:
   • "This Computer" — for a local backup (recommended if you have limited iCloud space).
   • iCloud — for automatic cloud backup (requires Apple ID and internet).
3. Click "Back Up Now".
4. Wait for completion (a message showing the last backup time will appear). Do not disconnect your iPhone until finished.

💡 Tip: For maximum security, create both types of backups (local and iCloud). You can encrypt the local backup by enabling the "Encrypt local backup" option (set a password).

Step 3: Check for Available Update

1. Remain on your iPhone's page in iTunes (or Finder).
2. In the "Version" section (or "Software Update" in Finder), click "Check for Update".
3. iTunes will connect to Apple's servers and check if a new iOS version is available for your model.
4. If an update is available, a window will appear showing the version name (e.g., iOS 18.3) and download size. Click "Download and Update".

⚠️ Important: If the "Check for Update" button is inactive or says "Your iPhone is up to date," but you know a newer version exists:

• Confirm your iPhone supports that version (older models may not receive updates).
• Try manually downloading the firmware (see the "Possible Issues" section).

Step 4: Download and Install the Update

1. After clicking "Download and Update," iTunes will start downloading the update file (a .ipsw file). The size can be 5-6 GB.
2. Do not disconnect your iPhone or close iTunes during download and installation.
3. After downloading, iTunes will automatically begin installation:
   • Your iPhone will restart.
   • A progress indicator (apple and loading bar) will appear on the screen.
   • Installation takes 10-20 minutes depending on the model.
4. Once complete, your iPhone will boot back into the operating system.

⚠️ Important:

• If an error appears during the process (e.g., 4013, 4005), don't panic. This is often a temporary glitch. Try again.
• Do not use your iPhone during installation.

Step 5: Set Up iPhone After Update

1. After restarting, your iPhone may show the welcome screen (like on first boot).
2. Go through the quick setup (language, region, Wi-Fi).
3. At the "Restore from Backup" step, choose:
   • "Restore from iCloud Backup" — if you backed up to the cloud (requires internet and time).
   • "Restore from Mac/PC" — if you backed up locally (faster).
4. Wait for the restore to finish (can take 20-60 minutes depending on backup size).
5. After restoration, your iPhone will restart and open to the home screen with your apps and data.

Verify the Result

Confirm the update was successful:

1. On your iPhone, go to Settings > General > Software Update.
2. It should display: "Your iPhone is up to date" and show the installed version (e.g., iOS 18.3).
3. Also check that key functions work (calls, internet, apps).

Possible Issues and Solutions

1. iTunes Does Not Detect iPhone

• Cause: Incorrect cable, lack of trust, outdated drivers (Windows).
• Solution:
  • Use an original Apple cable.
  • On iPhone: Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings, then reconnect.
  • On Windows: Update Apple Mobile Device drivers via Device Manager.

2. Error During Download/Installation (4013, 4005, 9, etc.)

• Cause: Connection failure, insufficient iPhone storage, corrupted firmware.
• Solution:
  • Ensure at least 5 GB of free space on your iPhone.
  • Restart both iPhone and computer.
  • Delete partially downloaded firmware: On Windows — C:\Users\Username\AppData\Local\Apple Computer\iTunes\iPhone Software Updates; on macOS — ~/Library/iTunes/iPhone Software Updates.
  • Try installing the update in recovery mode (create a backup first, as recovery mode erases data).

3. Update Stalls at "Preparing Update"

• Cause: Slow internet, firewall/antivirus blocking.
• Solution:
  • Temporarily disable antivirus and firewall.
  • Use a wired internet connection.
  • Temporarily disable VPN.

4. On macOS Catalina and Newer: Where to Update?

• Solution: Use Finder instead of iTunes:
  1. Connect iPhone to Mac.
  2. Open Finder, select your iPhone under "Locations" in the sidebar.
  3. Go to the general tab and click "Check for Updates".
  4. Subsequent steps are identical.

5. Insufficient Space on iPhone After Update

• Cause: Update requires temporary space to unpack firmware.
• Solution:
  • Free up 5-7 GB (delete unused apps, photos, videos).
  • Use the "Download Update" option in iTunes, then manually install via Settings > General > Software Update on your iPhone (the file remains in iTunes and installs without re-downloading).

💡 Tip: If nothing works, try updating your iPhone in DFU recovery mode. This is a more drastic method requiring a full iOS reinstall and restore from backup. Instructions: In iTunes, click "Restore iPhone" (while holding the power/home button depending on the model).