How to Fix "Trust This Computer" Not Appearing on iPhone

By ErrorFix · Updated October 16, 2026 · 6 min read

What "Trust This Computer" not appearing means

Every time you connect your iPhone to a computer it has never met, iOS is supposed to ask "Trust This Computer?" with a Trust / Don't Trust choice. Tapping Trust creates a cryptographic pairing between the phone and that computer, which is what allows iTunes, Finder, or Apple's backup tools to read the phone's data. The prompt only appears at the moment a new data connection is detected — and that is exactly why it can go missing: if the connection is not recognized as new data (bad cable, locked phone, previously stored answer), iOS has no reason to ask.

Most people hit this when they need to back up, restore, or update the iPhone through a computer, and the phone just sits there charging with no prompt and no sign of life in iTunes or Finder. The good news is the cause is almost never hardware failure on the phone itself. In the vast majority of cases it is one of three things: a cable problem (charging-only or damaged cables are the number-one culprit), a corrupted trust record (you tapped Don't Trust once, or the record went bad), or a software/driver problem on the computer side. Work through the steps below in order and you will almost always get the prompt back.

Common causes

• Charging-only or damaged cable: many cheap third-party cables carry power but not data, so the phone charges while the computer never sees it — no data connection means no trust prompt.
• Phone was locked when connected: iOS refuses to show the alert on a locked phone, and it only fires at the moment of connection — unlock first, then plug in.
• Corrupted or stored trust record: tapping "Don't Trust" once stores that answer, and a damaged trust record can stop the prompt from ever reappearing for that computer.
• Outdated iTunes, macOS, or iOS: an old iTunes on Windows may not recognize a newer iPhone, and Apple periodically fixes USB-trust bugs in iOS updates.
• Broken Apple USB driver on Windows: the "Apple Mobile Device USB Driver" is what lets Windows talk to the iPhone at all — if it is missing, outdated, or its service is stopped, the trust prompt can never trigger.

How to fix "Trust This Computer" not appearing — step by step

Work through these in order. Steps 1 through 3 alone resolve the issue for most people.

1. Swap the cable and port — charging-only cables hide the alert Unplug the iPhone and inspect your cable. Many cheap or worn cables are charging-only: they pass power but not data, so the phone charges while the computer never sees it — and no trust prompt ever appears. Use an Apple cable or a certified data cable, plug it directly into a USB port on the computer (not a hub, keyboard port, or monitor port), and try a second port. Also check for lint packed into the iPhone's Lightning or USB-C port: shine a light in, and if it looks dirty, gently sweep it out with a wooden toothpick. If the computer now recognizes the phone, retry and the prompt should appear.
2. Unlock the iPhone and keep the screen awake before plugging in iOS will not show the "Trust This Computer?" alert on a locked phone. Disconnect the cable, unlock the iPhone with your passcode or Face ID/Touch ID so you are on the Home screen, then plug the cable back in. Also open Settings, Display & Brightness, Auto-Lock and set it to Never while you troubleshoot, because if the phone sleeps within seconds the alert can vanish before you tap it. If the phone was already connected when you unlocked it, unplug and reconnect — the prompt only fires at the moment a new connection is detected.
3. Reset Location & Privacy to clear a corrupted trust record Every time you tap Trust, iOS stores a trust record for that computer. If that record is corrupted — or you previously tapped "Don't Trust" — the alert may never reappear for that computer. On the iPhone, go to Settings, General, Transfer or Reset iPhone, tap Reset, then choose Reset Location & Privacy and enter your passcode. This wipes all stored computer trust records (not your photos or data). Unplug the iPhone, wait ten seconds, reconnect it, and the "Trust This Computer?" prompt should appear immediately. This single reset fixes the issue for most people whose alert simply stopped showing.
4. Update iTunes or Finder and iOS to current versions An old version of iTunes on Windows (or macOS on older Macs) can fail to trigger the trust prompt with a newer iPhone. On Windows, open iTunes, go to Help, Check for Updates, and install the latest version — or better, uninstall iTunes and install the Apple Devices app from the Microsoft Store, which is Apple's current Windows companion app. On a Mac running macOS Catalina or later, the iPhone appears in Finder instead of iTunes: open System Settings, General, Software Update and install any macOS update. Then on the iPhone, go to Settings, General, Software Update and install any available iOS update, since Apple periodically fixes USB trust bugs in point releases.
5. Fix the Apple Mobile Device USB driver on Windows On Windows, the "Apple Mobile Device USB Driver" is what lets the computer talk to your iPhone — if it is missing or broken, no trust prompt will ever appear. Plug the iPhone in and open Device Manager (press Win+X and select Device Manager). Look under Portable Devices or Universal Serial Bus controllers for an Apple device entry with a yellow warning icon. Right-click it, choose Update driver, then Search automatically for drivers. If Windows cannot find one, reinstall iTunes/Apple Devices from Apple's site (not the Microsoft Store version, which sometimes skips the driver), or restart the "Apple Mobile Device Service": press Win+R, type services.msc, find Apple Mobile Device Service, and click Restart. Then unplug and reconnect the iPhone.
6. Restart both devices and test on a second computer Restart the iPhone (hold the side button and a volume button, slide to power off, then turn it back on) and restart the computer — a stuck USB session on either side can suppress the prompt. If it still does not appear, plug the iPhone into a different computer if you can: if the prompt appears there, the first computer's USB stack or security software is the problem — temporarily disable third-party antivirus or firewall software and retry. Also check that USB accessories are allowed: on the iPhone go to Settings, Face ID & Passcode (or Touch ID & Passcode), scroll to Allow Access When Locked, and make sure USB Accessories is turned on, or the phone blocks USB data entirely while locked.

Did this fix it? Quick checklist

• The "Trust This Computer?" alert appears on the iPhone within a few seconds of connecting
• Tapping Trust makes the iPhone appear in iTunes, the Apple Devices app, or Finder
• The computer can start a backup or sync without any further permission prompts
• Reconnecting later does not ask again for the same computer (the trust record saved correctly)

If the prompt still refuses to appear after all six steps, the problem is unusually stubborn but not hopeless. Try Apple's own cable on the computer's rear USB ports (front-panel ports and hubs are the most failure-prone), and if you have access to another computer, confirm the phone prompts there to rule out an iPhone-side fault. If the phone never prompts anywhere, back up over iCloud instead, then try a DFU restore through a computer — a clean restore rebuilds the USB trust stack entirely. On Windows, as a last resort, uninstall all Apple software (iTunes, Apple Devices, Apple Mobile Device Support), reboot, and reinstall from apple.com. Only if the phone also refuses to charge properly or drops connections randomly should you suspect a hardware fault in the charging port and visit an Apple Store.