Short answer: in order: swap the cable for a short data cable, plug the phone straight into the Mac to rule out the hub, set Auto-Lock to Never, make sure Low Power Mode is off, and re-trust the computer. On a rack, an underpowered hub is the most common cause — phones brown out and drop off while charging and working at once.
Start here: when does it disconnect?
| Pattern | Most likely cause | Go to |
|---|---|---|
| Never appears at all | Charge-only or faulty cable | Step 1 |
| Appears, then vanishes after a minute or so | Phone locking | Step 3 |
| Drops only when several phones are busy | Hub power | Step 2 |
| Drops at random, one phone only | Cable or port | Steps 1–2 |
| Appears but automation can't reach it | Untrusted profile or expired signing | Step 5 |
| All phones drop together | Hub power, Mac sleep, or power cut | Step 6 |
Step 1: the cable
The cable is the cause more often than anything else.
- Use a data cable. Charge-only cables never show the phone to the Mac.
- Keep it short and certified.
- Swap it for a cable you know works. If the problem follows the cable, bin it.
Step 2: the port and the hub
- Plug the phone straight into the Mac. If it stays connected, the hub is the problem.
- A hub that can't supply enough power while phones charge and work makes them brown out and disconnect. Use a powered hub sized for the phones on it — see USB hubs.
- Avoid chaining hubs. Give each hub its own Mac port.
Step 3: Auto-Lock and Low Power Mode
A phone that locks can drop off.
- Settings → Display & Brightness → Auto-Lock → Never.
- Low Power Mode off. Apple says Low Power Mode "sets Auto-Lock to 30 seconds," and it turns off by itself once the battery charges to 80% or higher (Apple Support, checked 17 September 2026). A phone that dips low can flip into it and start locking.
- "Never" missing? Community reports on Apple's forums tie that to managed-device or work profiles that enforce a lock (Apple Community). Check Settings → General → VPN & Device Management.
Step 4: trust
If the Trust prompt never appears or the phone keeps asking, reset it: Settings → General → Transfer or Reset iPhone → Reset → Reset Location & Privacy, then replug and tap Trust.
Step 5: the phone is connected but automation can't reach it
This looks like a disconnect but isn't.
- Developer profile untrusted: Settings → General → VPN & Device Management → Trust.
- Signing expired: with a free Apple account, profiles expire after seven days. See 7-day signing.
- Developer Mode off after a restore — see Developer Mode.
Step 6: everything drops at once
- Hub power supply failing or overloaded.
- Mac sleeping. Turn on "Prevent automatic sleeping when the display is off" in System Settings → Energy.
- Power blips. See power outages.
- Heat. A hot iPhone can slow or stop charging — see cooling.
With Farmero
Farmero resumes after disconnects, and a phone that drops mid-run stops only that phone's work until it comes back. If a run stops because the phone showed something unexpected, the saved evidence shows what was on screen. The troubleshooting page covers the runner-specific cases.
FAQ
Why does my iPhone connect and disconnect repeatedly?
Most often a poor cable, a hub short on power, or the phone locking. Test with a known-good data cable straight into the Mac with Auto-Lock set to Never.
Can Low Power Mode cause disconnects?
It can make the phone lock sooner: Apple says it sets Auto-Lock to 30 seconds. It turns off once the battery charges to 80% or higher.
Why is Auto-Lock Never greyed out?
Community reports link it to managed-device profiles that enforce a lock. Check VPN & Device Management for a profile.
Does a USB 3 hub fix disconnects?
Speed rarely fixes it. Power usually does. Use a powered hub sized for the number of phones.