Android file transfer keeps disconnecting on a Mac: causes and fixes

If Android file transfer on your Mac keeps disconnecting in the middle of a copy, start with the app. Google's old Android File Transfer is no longer offered or documented by Google, and the developer of OpenMTP, its free replacement, lists "frequent disconnects" among its faults. Switching to a maintained app is the first fix to try. If you are already on OpenMTP or MacDroid and the connection still drops, the documented causes are a second Mac app grabbing the phone, a poor cable or port, the phone's USB mode falling back to charging, and, in MacDroid, the wrong mount type.

This page sticks to causes that Google, OpenMTP, or MacDroid name in their own documentation. Where the documents are silent, we say so.

Symptom, cause, fix

Is the old Android File Transfer app the problem?

It is the first suspect. As of 1 October 2026 Google no longer offers Android File Transfer for download and its USB help page covers only Windows and Chromebook. Nobody is fixing the Mac app.

OpenMTP's developer wrote his app because of it. The project's README says the official app "comes with bugs, innumerable limitations, some of which include - not being able to transfer files larger than 4GB, frequent disconnections". That is a competitor's description, so weigh it accordingly, but it matches the complaint behind this search. OpenMTP's comparison table lists "Stable connection" as a difference between the two.

So the first fix is to stop using Android File Transfer, and to remove it so it cannot jump in. OpenMTP is free; setup is in how to use OpenMTP. If Android File Transfer will not connect at all, that is a different page: Android File Transfer not working on Mac.

Which apps steal the connection?

MTP, the protocol the phone uses over USB, allows one program at a time. MacDroid's MTP guide says the same thing as OpenMTP: "a phone cannot be accessed simultaneously by different services."

The documents describe this as a reason a file manager cannot reach the phone. None of them spells out what happens when a second app reaches for the phone halfway through a copy, but two programs competing for a one-at-a-time connection is the first thing to rule out, and it costs nothing. OpenMTP's guide names the usual suspects:

• Preview, Image Capture, Photos
• Google Drive, Dropbox, OneDrive
• Android File Transfer
• Garmin Express, iMovie, Lightroom
• On a Galaxy: Samsung Smart Switch, and Samsung Kies on older setups

OpenMTP's troubleshooting list adds a general warning: "Some applications might lock onto the USB port once they detect a USB drive." Quit these before a long transfer, not after it fails. MacDroid's FAQ notes a second option where the other app allows it: "disable working with MTP devices in its preferences."

Could it be the cable or the port?

Google's troubleshooting steps for USB transfers are short and worth following exactly:

1. "Try a different USB cable. Not all USB cables can transfer files."
2. "To test the USB port on your device, connect your device to a different computer."
3. "To test the USB port on your computer, connect a different device to your computer."

Google files these under its Windows instructions, but a cable test is the same on any computer. OpenMTP's connection guide adds the simplest step of all: "try unplugging it and plugging it back in". If the drop happens when the phone or the cable moves, you have found the cause.

Does the phone locking or sleeping break the transfer?

We could not find a Google, OpenMTP, or MacDroid page that says a phone locking mid-copy ends an MTP session, so we will not state it as a cause. What the documents do say is that the connection has to start with the phone unlocked: it is the first step in Google's instructions and in OpenMTP's.

If you want to rule the screen out during a long copy, there is a documented setting for it. Android's developer options page lists Stay awake, which "sets your screen to stay on while the device is plugged in". It lives in Developer options, a menu intended for app development, so turn it off again when you are done. Or simply keep the phone unlocked and tap the screen now and then.

Is wireless more reliable than a cable?

It removes the USB causes: no cable, no USB mode, no MTP rule about one app at a time. It brings a different dependency, the Wi-Fi network. We have not measured either, so we will not tell you which fails less.

The Relay is a wireless option. Its file transfer and browsing shows the phone's storage in a Mac window and you drag files either way over your local network, with no file-size limit set by the app. It costs $19.99, paid once. It has no USB mode, so it is not a fix for a cable setup you want to keep, and for a one-off bulk copy a good cable with OpenMTP is free. Free wireless senders are compared in NearDrop or LocalSend, and the trade-offs in USB or wireless for Android to Mac transfers.

A fair test: copy the same large folder three times by cable and three times over Wi-Fi, and count the failures.

Questions people ask

Why does Android File Transfer disconnect during large files?

OpenMTP's site says Google's app cannot copy files over 4 GB and disconnects constantly. Google has not documented the app's limits, and no longer maintains a Mac page for it. Use OpenMTP, whose site says it handles files larger than 4 GB.

Does OpenMTP disconnect too?

Its documentation covers a blank screen and a device that stops being recognised. The troubleshooting list starts with rebooting the Mac and quitting conflicting apps, and includes turning off Hotplug detection in Settings.

Will keeping the screen on stop the disconnects?

It might help you rule the phone out, and Android documents a Stay awake option for it. No source we found names screen lock as a cause, so check the app conflicts and the cable first.