# Samsung Auto Blocker blocks USB debugging: how to fix it

On recent Samsung Galaxy phones, Auto Blocker blocks commands sent over a USB cable, which is exactly what ADB sends. If the phone connects but nothing happens and the "Allow USB debugging?" prompt never appears, switch Auto Blocker off while you work.

## Symptoms

- The computer sees the phone but commands do nothing.
- The "Allow USB debugging?" prompt never appears.
- USB debugging is on and the cable is a data cable, yet the connection fails.

## Fix

1. Open **Settings > Security and privacy > Auto Blocker**.
2. Switch Auto Blocker off, or turn off its option to block commands and software updates by USB cable.
3. Unplug and replug the cable, unlock the screen and press **Connect phone** in the [slimdroid tool](https://slimdroid.com/app).
4. Tap **Allow** on the "Allow USB debugging?" prompt.

## Put it back afterwards

Auto Blocker exists to stop USB attacks, so it should end up on. Samsung turns it back on by itself after about 30 minutes; keep that automatic re-enable switched on rather than disabling it for good. It is your safety net if you forget. If commands stop working partway through a session, it has re-armed: switch it off again and reconnect. Also switch USB debugging off and revoke authorizations when you finish; [enable USB debugging](https://slimdroid.com/guides/enable-usb-debugging) covers the whole cycle.

### Is turning Auto Blocker off dangerous?

It lowers a protection while it is off. Keep the phone locked while connected, use your own cable and computer, and leave Samsung's automatic re-arm (about 30 minutes) switched on so it protects you again even if you forget.

## Related guides

- [How to enable USB debugging on Android](https://slimdroid.com/guides/enable-usb-debugging)
- [How to debloat an Android phone without root](https://slimdroid.com/guides/debloat-android-without-root)
- [Samsung bloatware: what is safe to disable on a Galaxy phone](https://slimdroid.com/guides/samsung-bloatware-what-to-disable)