Direct answer
Confirm that the cable carries data, Android USB mode is File transfer, and USB debugging is enabled. If the device remains missing, revoke and reauthorize USB debugging and reconnect it. If the interface is busy, close Android Studio and run adb kill-server.
Troubleshoot by symptom
| Symptom | Check first |
|---|---|
| Phone missing from the chooser | Cable, File transfer mode, USB debugging, reconnect |
| Phone appears but authorization fails | Unlock the screen, approve the RSA fingerprint, revoke old authorizations |
| Device is busy | Close Android Studio, scrcpy, and the desktop ADB server |
| Previously connected device is offline | Refresh authorized devices, reconnect USB, and choose the device again if needed |
| Connection ends when the panel closes | This is the current session boundary; keep the side panel open during capture |
Full recovery sequence
- Use a known data-capable USB cable and another computer port.
- Choose File transfer in the Android USB notification.
- Toggle USB debugging and revoke existing debugging authorizations.
- Exit every desktop program that may use ADB.
- Reconnect the phone and authorize it in both the browser and Android prompts.
Information to collect if it still fails
- Desktop operating system and full Chrome or Edge version.
- Phone brand, model, and Android version.
- Whether the browser chooser lists the device and the exact error text.
- Whether the official adb devices command can see the same phone.
Frequently asked questions
Why is the Android phone missing from Chrome's device chooser?
First verify that the USB cable carries data, Android USB mode is File transfer, and USB debugging is enabled. Then reconnect the phone and open the chooser again.
Why does WebUSB say the device is busy?
Android Studio, scrcpy, or a desktop ADB server is usually holding the USB ADB interface. Close those programs and run adb kill-server before retrying.
Why does the connection end when the TabQA side panel closes?
The WebUSB session belongs to the extension side-panel page, so closing it ends the current device session. Evidence that was already saved remains available.