When your iPhone refuses to update, the issue typically stems from device eligibility, insufficient storage, battery level, network connectivity, or software glitches. Start by verifying your iPhone model supports the latest iOS version—only devices from iPhone XR or newer (for iOS 18) or iPhone 11 series or newer (for iOS 26) are compatible ^[7][9]. Ensure your battery is charged to at least 50% and you have 5-10GB of free storage space, as updates require significant resources ^[1][4]. A stable Wi-Fi connection is mandatory, and Apple’s servers must be operational (check Apple System Status) ^[4][6]. If these basics are covered, proceed with troubleshooting steps like restarting your device, deleting and redownloading the update, or using a computer for the installation ^[1][2].

• Critical first steps: Check model compatibility (iPhone XR+ for iOS 18, iPhone 11+ for iOS 26) and ensure 50% battery + 5-10GB free space ^[7][8]
• Network requirements: Use Wi-Fi (not cellular data) and verify Apple server status ^[4][6]
• Advanced fixes: Restart the device, delete and redownload the update, or use a Mac/PC via Finder or iTunes ^[1][5]
• Last resort: Enter recovery mode if the iPhone is stuck or unrecognized by the computer ^[2]

Step-by-Step Solutions for iPhone Update Failures

Pre-Update Checks: Compatibility, Storage, and Power

Before attempting any fixes, confirm your iPhone meets the fundamental requirements for the update. Compatibility is the most common roadblock—older models like iPhone X or earlier cannot run iOS 18 or later, while iOS 26 drops support for 2018 devices (iPhone XR, XS, XS Max) ^[7][9]. Storage is another frequent issue: iOS updates require 5-10GB of free space, depending on the version. Users report updates failing even with 2-3GB available, so aim for at least 10GB to avoid errors ^[8][3].

• Device eligibility for iOS 18: iPhone XR, XS, 11, SE (2nd gen), and newer ^[7]
• Device eligibility for iOS 26: iPhone 11 series and later (excluding iPhone XR/XS) ^[9]
• Storage requirement: Minimum 5GB free, but 10GB recommended to prevent installation errors ^[3][8]
• Battery level: Must be 50% or higher; connect to power if below this threshold ^[1][4]
• Network: Wi-Fi connection required (cellular data updates are blocked for large files) ^[6]

To check storage, go to Settings > General > iPhone Storage and review the color-coded breakdown. Delete unused apps, clear Safari cache, or offload photos to iCloud to free up space ^[8]. For battery, plug in your iPhone if it’s below 50%, or enable Low Power Mode temporarily (though updates may still fail in this mode) ^[7].

Troubleshooting Steps: From Restarts to Recovery Mode

If your iPhone meets all prerequisites but still won’t update, follow this escalating series of fixes, starting with the simplest solutions.

1. Restart your iPhone

A soft restart resolves temporary software glitches that may block updates. The method varies by model:

• iPhone 8 or later: Press and release Volume Up, then Volume Down, then hold the Side button until the Apple logo appears ^[4]
• iPhone 7/7 Plus: Hold Volume Down + Side button simultaneously ^[1]
• iPhone 6s or earlier: Hold Home + Side/Top button ^[6]

1. Delete and redownload the update

Corrupted download files can halt the process. To fix:

• Go to Settings > General > iPhone Storage
• Locate the iOS update file (usually labeled “iOS [version]”) and tap Delete Update ^[1]
• Return to Settings > General > Software Update and download the update again

1. Update via computer (Finder/iTunes)

If over-the-air updates fail, use a Mac or PC:

• Mac (macOS Catalina or later): Connect iPhone to Mac, open Finder, select your device, and click Check for Update ^[5]
• PC or older Mac: Use iTunes, select your iPhone, and click Update (not Restore) ^[2]
• Ensure your computer is updated to the latest OS version to avoid compatibility issues ^[2]

1. Enter recovery mode (last resort)

Use this if your iPhone is stuck on the Apple logo or shows a “Connect to Computer” screen:

• iPhone 8 or later: Press and release Volume Up, then Volume Down, then hold Side button until recovery mode appears ^[2]
• iPhone 7/7 Plus: Hold Volume Down + Side button ^[2]
• In Finder/iTunes, select Update (not Restore) to reinstall iOS without erasing data. If this fails, choose Restore, but this will wipe your device ^[2]

1. Check for malware (rare but possible)

While iPhones are less prone to malware, some users report update blocks due to suspicious profiles or apps. To check:

• Go to Settings > General > VPN & Device Management and remove any unfamiliar profiles ^[4]
• Review recently installed apps and delete any from untrusted sources

1. Contact Apple Support

If all else fails, Apple’s official support can diagnose hardware issues or server-side problems. Visit Apple Support or schedule a Genius Bar appointment ^[3].

• Most effective fixes in order:
• Restart iPhone (resolves 30-40% of update issues) ^[4]
• Delete and redownload the update (fixes corrupted files) ^[1]
• Use a computer for the update (bypasses OTA errors) ^[5]
• Recovery mode (for stuck devices) ^[2]
• Check for malware or unauthorized profiles ^[4]