Work through them in this order
Not because the later ones are unlikely, but because each one masks the ones after it. A phone that Windows cannot reach at all will never get as far as telling you Developer Mode is off.
- The computer has no way to talk to an iPhone. Windows only.
- The phone has not trusted this computer, or is locked.
- Developer Mode is off on iOS 16 or newer.
- The cable or the port. Rarer than the internet suggests, but real.
1. Apple Mobile Device Support is missing
The message, verbatim:
Apple Mobile Device Support isn't running. Install the Apple Devices app (or iTunes) from the Microsoft Store, then reconnect your device.
This one is Windows-specific and it is the single most common cause. Windows ships no
mechanism for talking to an iPhone over USB. That mechanism, Apple's USB multiplexer
listening on 127.0.0.1:27015, arrives with Apple's own software and with
nothing else. Every tool in this category depends on it, whether or not it says so.
The fix, in order:
- Install Apple Devices from the Microsoft Store. It is free. iTunes works equally well and installs the same service, so if you already have iTunes you have nothing to do.
- Restart the PC. The installer does not insist on it and the service registers at boot, which is why a fresh install so often still shows nothing.
- If it still fails, open Services and look for Apple Mobile Device Service. If it is present but stopped, start it. If it is present and running, the problem is further down this page.
On a Mac there is no equivalent step. macOS ships the same multiplexer itself, which is why the Mac guide has no install section at all.
2. The phone has not trusted this computer
Three related messages, and they mean three different things:
This device hasn't trusted your computer. Unlock it, then tap Trust on the "Trust This Computer?" prompt.
Trust was declined on the device. Disconnect it, reconnect, and tap Trust when asked.
Unlock the device with its passcode, then try again.
The trust prompt is refused silently while the phone is locked, so a phone sitting face-down on a desk will look as though it declined when it was never actually asked. Unlock it first, then plug it in, then answer the prompt and enter the passcode when it follows.
If the prompt does not appear at all, unplug, wait a couple of seconds, and plug back in. If it still does not appear, the phone believes it has already answered, so reset the record with Settings → General → Transfer or Reset iPhone → Reset → Reset Location & Privacy, then reconnect. That clears trust for every computer, not just this one, which is worth knowing before you do it.
3. Developer Mode is off
Developer Mode is off. On the device open Settings → Privacy & Security → Developer Mode, turn it on, and restart the device.
Required on iOS 16 and newer only. Apple added it as a per-device opt-in so that the developer services which used to be reachable on any trusted phone are reachable only on a phone whose owner asked for it. Location simulation is one of those services.
The part that catches people: the Developer Mode menu item does not exist until the phone has been connected to a computer running developer tooling at least once. If you look before you plug in, it will not be there, and it will look as though your iOS version does not have it. The full walkthrough, including that case.
4. The cable, or the port
Blamed constantly and guilty occasionally. A cable that charges is not necessarily a cable that carries data: some very cheap third-party cables are wired for power only, and the symptom is a phone that charges happily and never appears to any software. Front-panel USB ports on desktop PCs are the other repeat offender.
The test is thirty seconds: try the cable that came with the phone, and try a port on the back of the machine. If the phone appears in File Explorer or Finder, the cable is fine and the problem is elsewhere on this page.
The other messages, and what they mean
Draftpin reduces every device failure to one of a small closed set of codes, each with a fixed remedy, so nothing ever surfaces as a stack trace. The ones not covered above:
-
DEVICE_BUSY: another program is already using the device. iTunes, Finder, Xcode and backup software all hold it exclusively at times. Close the other one. -
NEEDS_ELEVATED_TUNNEL: the phone is on iOS 17.0 to 17.3, where Apple's transport needs a tunnel only an administrator can create. Updating the phone to iOS 17.4 or later removes the requirement entirely. This is not a Draftpin limitation and it affects every tool equally. -
DDI_NOT_MOUNTED: the Developer Disk Image has not been mounted yet. Keep the phone connected and unlocked; it resolves itself. -
DDI_UNAVAILABLE: no Developer Disk Image is published for that iOS version, so location simulation cannot be enabled on it. Usually a very new beta. -
TUNNEL_FAILED: the secure tunnel to the device did not come up. Unplug, plug back in, try again. Persistent failures are usually a third-party USB hub. -
CONNECTION_LOST: the cable moved, the phone rebooted, or the port dropped. The phone returns to its real location the moment this happens, which is the intended behaviour rather than a fault.
Draftpin has a copy diagnostics button that bundles the tail of its log, which is the fastest way to get an answer out of anyone trying to help you. It contains no coordinates and no device identifiers beyond the ones needed to say which model and iOS version failed.
Questions
Why is my iPhone not detected on Windows?
Almost always because Apple Mobile Device Support is not installed or not running. Windows has no built-in way to talk to an iPhone; that arrives with Apple's free Apple Devices app from the Microsoft Store, or with iTunes. Install one of them and restart the PC. If the phone charges but never appears anywhere, the other common cause is a charge-only cable.
What does AMDS_MISSING mean?
Apple Mobile Device Support is not running on the computer. It is the Windows service that provides the USB channel to an iPhone, and it is installed by the Apple Devices app or by iTunes. Install either one, restart, and reconnect the device.
Why does my iPhone say Trust This Computer every time?
The trust record is stored against the pairing between that phone and that computer, and it is discarded if the phone is reset, if Reset Location & Privacy is used, or if the pairing record on the computer is removed. Unlock the phone, tap Trust, and enter the passcode when it asks. The prompt is ignored if the phone is locked, which is why it can appear to be refused when it was never really answered.
Why is Developer Mode required to simulate a location?
Apple added Developer Mode in iOS 16 as a per-device opt-in for the developer services that were previously reachable on any trusted phone. Location simulation is one of those services, so on iOS 16 and newer the toggle has to be on. It is in Settings, then Privacy and Security, then Developer Mode, and the phone restarts to apply it.
Does an iPhone need to be unlocked to simulate a location?
It needs to be unlocked to establish the connection, because a locked device refuses the pairing and developer service handshakes. Once a session is running the phone can be locked again and the simulated location continues.
Once it's talking
Pick up where you left off.
Draftpin is free to start, and the whole procedure takes about a minute once the phone is visible.