Setting up
About two minutes, once.
The app walks you through all of this and ticks each step off by itself as you do it. This page is the same thing in writing, for when you want to read ahead or you are helping somebody else.
1. Turn on the file system extension
macOS will not let an app provide a file system until you say so. In System Settings, open General, then Login Items and Extensions. Scroll to the bottom, to Extensions.
Switch that list to By Category. This matters: under By App the File System Extensions row does not exist, which is where most people get stuck. Open File System Extensions and turn SideMount on.
The button in the app opens that exact pane for you.
2. Turn on USB debugging on the phone
Android hides this behind a small ritual. On the phone:
- Open Settings, then About phone.
- Tap Build number seven times. The phone will tell you that you are now a developer.
- Go back, open Developer options, and turn on USB debugging.
The wording moves around between makers. On Samsung, Developer options sits at the bottom of the main Settings list. On Xiaomi, tap MIUI version rather than Build number.
3. Plug the phone in and tap Allow
The phone asks whether to trust this computer. Tap Allow, and tick Always allow from this computer so it stops asking.
If no prompt appears, unlock the phone first. Android will not show it on a locked screen.
That is it
The phone appears in the SideMount panel with a Mount button, or mounts by itself if you left that setting on. Open it in Finder from there.
When something is wrong
The phone does not appear at all
It is the cable, four times out of five. A cable that came with a power adapter often has no data lines. Try the one that came with the phone, and a different port.
It says the phone is waiting to be allowed
Unlock the phone and look for the prompt. If you have dismissed it before, go to Developer options and tap Revoke USB debugging authorisations, then unplug and plug in again.
A mount fails, and then they all do
macOS runs the file system service, and it can get into a state where nothing will mount, including Apple's own file systems. Apple does not allow that service to be restarted, so the cure is a restart of the Mac. Ejecting normally rather than yanking the cable is what avoids it.
Another program is holding the phone
A phone offers one connection at a time. If you have Android Studio or an adb server running, quit it and press Reconnect in SideMount's settings.
Still stuck? Email us and say what the app shows you. It is a small enough operation that you will get a real answer.