adb device offline: Causes and How to Fix It
Why adb devices lists your phone as offline, over USB or Wi-Fi, and the fixes that work, from restarting the adb server to updating platform-tools.
adb devices shows your phone, but with the word offline instead of device:
List of devices attached
R58M123ABC offlineOffline means the adb server can see the phone, but the two sides failed to finish the ADB handshake, or the connection broke. Commands such as adb shell or adb install fail with error: device offline. Here are the causes, from most to least common.
1. Restart the adb server
A stale server is the most frequent cause, especially after the phone slept, rebooted or switched USB modes.
adb kill-server
adb start-server
adb devicesUnplug and plug the cable back in after restarting the server.
2. Unlock the phone and check for a prompt
On the first connection to a computer, the phone shows Allow USB debugging?. While it waits for you, some versions of adb show offline instead of unauthorized. Unlock the screen and tap Allow. If no prompt appears, go to Developer options, tap Revoke USB debugging authorizations, turn USB debugging off and on, and reconnect.
3. Update platform-tools
An old adb client can fail the handshake with a newer Android version and report offline. Check your version:
adb versionIf it is several years old, download the latest Android SDK platform-tools from Google, and make sure your PATH does not still point at an older copy (Android Studio, Genymotion and some phone suites ship their own adb).
4. Two programs fighting over the phone
Android Studio, scrcpy, phone manager apps, emulators and vendor PC suites can each start their own adb server. Different server versions keep restarting each other and the phone flips to offline. Close the other tools, then restart the server as in step 1. More in fixing a busy or unauthorized device.
5. Cable, port and USB mode
- Try another cable that is known to carry data, and a USB port directly on the computer, not a hub.
- On some phones, switching the USB mode from Charging only to File transfer in the USB notification helps the connection settle.
6. Over Wi-Fi: the connection dropped
A phone connected with adb connect goes offline when Wi-Fi sleeps, the IP changes or Wireless debugging switches off.
adb disconnect 192.168.1.20:5555
adb connect 192.168.1.20:5555If that fails with Connection refused, network mode is off. See fixing Connection refused.
7. Restart the phone
When nothing else works, restart the phone and the computer. It clears a stuck adbd on the phone and stale USB drivers on the computer.
How ADBKit handles it
ADBKit does not use the adb server on your computer. Chrome or Edge talk to the phone directly with WebUSB, so a server version mismatch cannot make a device offline in ADBKit. It does need the USB connection to itself: if another program's adb server holds the phone, ADBKit says the device is busy and tells you what to close. Over Wi-Fi, ADBKit shows a clear "connection lost" state and offers to reconnect.
If adb devices shows nothing at all, see adb devices shows no devices.