GPSLarp can't find my iPhone
The app says the connection is up and the device list is empty. Or it never gets that far and says it could not start the connection at all.
Those are two different problems with two different fixes, and the app words them differently on purpose. Read which message you have before doing anything else — most of the time lost to this is spent fixing the other one.
01Which message do you have
"Tunnel is up, but no iPhone detected." The connection to the phone started fine. The Mac looked for a device for a few seconds and found none. Go to what causes it below.
Anything about the connection failing to start. The connection never came up, so no phone could have been found whether one was there or not. That is almost always the administrator prompt — see the administrator password.
A sign-in screen covering the window. Not this problem at all. GPSLarp checks who you are before it reaches any device, deliberately: a signed-out user is never shown a password prompt for a connection they are not going to be allowed to use. See sign-in trouble.
02What causes an empty device list
Three things, and the app tells you all three together rather than identifying one. That is a real limitation and worth knowing before you start guessing: it can tell a connection that failed to start from a connection that is up with nothing behind it, but for the second case it offers the remaining causes as a list. Anything claiming a precise diagnosis would be describing something nobody has built.
- The Mac and the iPhone have never been introduced. iOS will not answer a computer it has not been told to trust, and that grant only happens over a cable, once, with the phone unlocked.
- You are on Wi-Fi and the two devices are on different networks. A guest network, a 5 GHz band the Mac is not on, a VPN on either device, or a router with client isolation switched on all look identical from here: nothing to find.
- The phone is locked, or has been asleep long enough to stop answering. A locked iPhone is not reliably reachable.
On iOS 16 and later there is a fourth possibility that looks exactly like the first three, and it has its own page: Developer Mode. The services GPSLarp drives are the ones Apple's own developer tools use, and iOS keeps those behind a switch that is not visible until a computer has asked for it.
03Work through it in this order
01Plug the cable in and unlock the phone
Not because the cable is required afterwards — it is not — but because it settles the pairing and the network question in one move. A phone that has been plugged in and unlocked at least once stays reachable over Wi-Fi afterwards, so this step is the shortest path through two of the three causes at the same time.
Use a cable that carries data. A charge-only cable will power the phone and pass nothing, which produces exactly this symptom and no error anywhere.
02Answer the trust prompt
With the phone unlocked and plugged in, iOS asks whether to trust this computer, and then asks for the phone's passcode. Both are required — the prompt on its own does nothing until the passcode confirms it.
03Ask GPSLarp to look again
The Mac only searches for a few seconds after the connection comes up. If the phone finished unlocking after that window closed, there is nothing wrong except the timing — refresh the device list rather than restarting anything.
04If you want it over Wi-Fi, check it is the same Wi-Fi
Compare the network name on the Mac with the one on the phone, letter for letter. Then turn off any VPN on either device: a VPN on the Mac routes it away from its own local network, and the phone becomes unreachable without anything appearing to be wrong.
Guest networks and networks with client isolation deliberately stop devices seeing each other. There is no setting in GPSLarp that works around that, because the block is in the router.
05Check Developer Mode, on iOS 16 or later
Settings › Privacy & Security › Developer Mode. If the row is not there at all, that is the normal state until a computer has asked for it — the Developer Mode page covers how to make it appear and the restart it needs.
04If that did not work
Three things left, in order of how often they are the answer.
- Try the other end of the cable. A different USB port and a different cable eliminate the single most common cause of a device that is plugged in and invisible. This costs a minute and settles it.
- Restart both devices. Unsatisfying, and it clears a stuck pairing daemon on either side more often than it has any right to.
- Reset the phone's trusted computers. This is the heavy one and it clears every computer the phone has ever been paired with, not only this Mac. It is on the Trust This Computer page with what it costs.
One thing worth stating plainly rather than leaving you to infer it: GPSLarp is only ever tested against hardware the people writing it own, and no iOS version has been checked against it. If the phone still does not appear after all of the above, the honest answer is that nobody here can tell you why from a distance.