ADB Android Device Unauthorized

Question 1

It's likely that the device is no longer authorized on ADB for whatever reason.

1. Check if authorized:

<ANDROID_SDK_HOME>\platform-tools>adb devices
List of devices attached
4df798d76f98cf6d        unauthorized

2. Revoke USB Debugging on phone

If the device is shown as unauthorized, go to the developer options on the phone and click "Revoke USB debugging authorization" (tested with JellyBean & Samsung GalaxyIII).

3. Restart ADB Server:

Then restarted adb server

adb kill-server
adb start-server

4. Reconnect the device

The device will ask if you are agree to connect the computer id. You need to confirm it.

5. Now Check the device

It is now authorized!

adb devices
<ANDROID_SDK_HOME>\platform-tools>adb devices
List of devices attached
4df798d76f98cf6d        device

Question 2

Try forcing ADB to create new keys.

On Linux/OSX:

  $ mv ~/.android/adbkey ~/.android/adbkey.old
  $ mv ~/.android/adbkey.pub ~/.android/adbkey.pub.old
  $ adb kill-server
  $ adb start-server

On Windows 10 (thank you, Pau Coma Ramirez, Naveen and d4c0d312!):
- Go to %HOMEPATH%\Android\.android\
- Look for files called adbkey or adbkey.pub.
- Delete these files. Or, if you want to be on the safe side, move them to another directory.
- Repeat the above steps in %USERPROFILE%\.android\
- Try again

After this I didn't even need to unplug my phone: the authorization prompt was already there.

Question 3

Ohhh finally I figured it out! After removing Eclipse directory I installed it into another directory.

echo %ANDROID_SDK_HOME%

has displayed wrong path to sdk directory.

set ANDROID_SDK_HOME "E:\adt-bundle-windows-x86_64-20140321\sdk"
unplug device
adb kill-server
adb start-server
plug device

After these steps, I was able to see confirmation dialog with RSA fingerprint on my phone :)

Question 4

I run into the same issues with nexus7.

Following worked for fixing this.

Open Developer option in the Settings menu on your device.
Switch off the button on the upper right of the screen.
Delete all debug permission from the list of the menu.
Switch on the button on the upper right of the screen.

now reconnect your device to your PC and everything should be fine.

Sorry for my poor english and some name of the menus(buttons) can be incorrect in your language because mine is Japanese.

Question 5

I had the same problem. It was resolved by setting "USB computer connection" to "Camera (PTP)" instead of "Media Device (MTP)

Question 6

I wasted hours on this stupid issue. None of the above solutions worked for me on their own.

I'm running Windows 10. I had an old manual install of the Android SDK as well as Android Studio's SDK. I deleted my manually installed SDK and all my devices stopped working. These were the symptoms:

$ adb usb
error: device unauthorized.
This adb server's $ADB_VENDOR_KEYS is not set
Try 'adb kill-server' if that seems wrong.
Otherwise check for a confirmation dialog on your device.

as well as

$ adb devices
List of devices attached
id1        unauthorized
id2        unauthorized
id3        unauthorized

To be honest I'm not sure which of these steps got me my Allow USB debugging? prompts back so I listed EVERYTHING for completeness. Goes in order from easiest to hardest. Most people seem to be back on their feet after the first two sections.

Restart ADB

I would perform this after each of the sections below.

adb kill-server
adb usb

Go crazy with developer options

Turn Developer options off and back on
Turn USB debugging off and back on
Revoke USB debugging authorizations. Try this while USB debugging is on and if possible try also when USB debugging is off.

Replug devices

Unplug and replug USB cable into phone.
Switch physical ports on your PC that your USB cable is connected into
Switch physical USB cables you're using to connect your devices

Start rebooting everything

Reboot all your devices and connect again
Reboot your PC
Toggle WIFI on and off

Start deleting things

CAUTION Delete your ~/.android folder. Sometimes this folder can have the wrong permissions which can cause issues. You might want to back this folder up first.
Uninstall all manufacturer specific drivers from add/remove programs. I uninstalled the following (names are not exact)
- LG United USB Driver
- HTC Mobile USB Driver
- OnePlus USB Drivers 1.00
- Samsung USB Driver
I also uninstalled all emulators and their respective drivers (optional)
- Nox & related drivers
- Bluestacks
- Genymotion

Erase all Android related environment variables.

Delete %ANDROID_HOME% if you have it set
Delete %ANDROID_SDK_HOME% if you have it set

At this point all my devices magically came to life and started displaying the Allow USB debugging? prompts and connecting properly through ADB. If you've made it this far and haven't found a solution, I am truly sorry you're in this predicament. Make sure you've restarted all devices and your dev machine at the end of all of these steps and connect to a fresh USB port using a new cable.

If that still doesn't work try some of these other SO posts on the subject:

Question 7

For me, I firstly unauthorized my device accidentally which I found out later. To revert it back to reauthorise:

Disconnect USB device from laptop/computer
Click 'Revoke USB debugging authorisations' in Developer options.
Disable developer options on top.
re-enable it again.
enable USB debugging
run command 'adb kill-server' on terminal
run command 'adb start-server' on terminal
connect your mobile device to laptop/computer
reauthorize
press like)

Note: if above doesn't work, trying restarting your laptop before connecting again

Question 8

Steps that worked for me:
1. Disconnect phone from usb cable
2. Revoke USB Debugging on phone
3. Restart the device
4. Reconnect the device
The most important part was rebooting the device. Didn't work without it .

Question 9

After having spent over an hour going in rounds swearing at Samsung (mostly), Google, and who not, here are my findings, that finally helped me get the device recognized:

On Device:
- Set developer mode
- Allow USB debugging
- Default USB configuration > Select USB tethering
- Connect device to PC USB
On PC:
- Elevated cmd/ps prompt (maybe not mandatory, but that was my drill)
- adb kill-server (precede with .\ in ps)
- adb start-server (while device connected) > watch for prompt on device
On device:
- Always allow connections from this computer > Yes
On PC:
- adb devices gets the following output:

List of devices attached
278c250cce217ece        device

Question 10

For reference, I just encountered much the same issue on Linux and had a hell of a time figuring it out. I eventually determined that I had a ~/.android directory that was root owned (thanks to running adb as root, while flailing around trying to figure out other connection problems). Deleting that root owned ~/.android directory resolved the missing authorisation dialog next time I reconnected the device.

It's possible that simply changing the ownership would also have fixed the problem - I'm guessing it was a simple lack of access to the adb key file stored inside that was the root of the problem. I didn't verify that, though, and I'm not going to deliberately break my hard-won connectivity just so I can check ;-)

Question 11

Had similar issue on osx and Nexus 5 (A6.0.1). I did get the authorization pop-up and confirmed it, despite that Android Studio nor any other IDE could connect to device.

Turned out my Nexus (rooted) was missing key files.

Rebooted Android device into recovery
Ran code pasted below
Rebooted Android device, adb now identifies device

Push key from computer to Android device:

 cd ~/.android && adb push adbkey.pub /data/misc/adb/adb_keys

Solution came from here

Question 12

Recheck 'USB Debug' option in developer options helped me

Question 13

I was getting this error with my Nexus 10. I tried all of the answers I could find, and then I realized I was using a different USB port than usual. I switched to using the port I usually use, which is on the other side of my laptop, and the authorization popped up on my tablet!

Question 14

As the message have stated, you need to allow the adb access on your phone.

You need to first connect the phone to your PC with USB cables, then the authorization message will pop out on the screen. Tick remember your choice, then allow it.

IF your device doesnt shows any messages when connected to the PC.Just do this.

Remove /data/misc/adb/adb_key, reboot your phone and try connect again. The message should come up.

Question 15

The solution is to copy your file ~/.android/adbkey.pub (on GNU/Linux, or %USERPROFILE%\.android\adbkey.pub on Windows) to Android, and place it as /data/misc/adb/adb_keys. You need root privileges to do that.

You can transfer the file any way you like (or are able to), be it USB, e-mail or a temporary file upload service. In my case, as it was a new Android-x86 installation in a Virtual Machine, no usable web browser, and with network/TCP adb not working, I had to actually type in the 715 characters.

At least it worked.

Question 16

If you are on ubuntu, try running the server as root:

sudo adb kill-server

sudo adb start-server

Question 17

Simply, turn off developer options from your device and again turn on, attach USB with the device and working system and turn on USB debugging.

Question 18

I was tiered with this, I got that permission dialog by turning off wi-fi of my phone.

Question 19

I was not getting the RSA fingerprint pop up on my phone.

I had to go into the

  C:\Users\<userName>\.android\adbkey and adbkey.pub

files, delete those and then do kill and restart of adb server. I had to stop and restart the debugger and connecting as USB in PTP mode.

Because the RSA authorisation key was getting stored in this path, killing and restarting the adb server didn't help.

Question 20

Disconnect your device from the computer.

Go into developer settings.

Turn off developer settings.

Turn on developer settings.

Enable USB Debugging (and whatever other settings you enabled beforehand)

Reconnect your device to the computer.

Try again.

Worked for me so hope it works for you!

Question 21

This solved my issue!

run your android simulator
go to setting and enable developer mode
enable from the developer settings usb debugging

at this point you will get popup massage at you emulator to authorise the device and you are good to go :)

Question 22

You should delete the file: c:\users\_user_name_\.android\adbkey

Question 23

On some Samsung devices the mode change that can be set by dialing *#0808# doesn't stick without direct reboot. Once rebooted, dial the same string and make sure that you have adb + mdp selected and USB set to AP. After this make sure to reconnect phone and restart ADB server. Also try to avoid USB hubs and virtual machines witch surely complicate matter further. The follow the previously mentioned instructions for clearing authorized devices etc.

Question 24

I had a similar problem. However, it was solved using a different solution. I thought I might share this here as well. Let me describe my problem first.

I had the Android SDK in my ubuntu. The path to the android SDK was not in the environment variable path. I installed adb using a apt-get command and it could not find the sdk home folder and hence, it was showing the unauthorized error and the device was not popping up anything as well. I got stuck here.

Then I uninstalled the adb using apt-get purge which I installed earlier. The Android SDK has the adb program in the platform-tools folder. I just add the path to the environment variable and it worked like a charm.

export PATH=${PATH}:/home/YOUR-USERNAME/path/to/adb
adb devices
List of devices attached
f7f716d56905    device

Hence the problem was not setting the Android SDK to the environment variable path.

Question 25

The same issue started appearing once I changed my development device, it was solved as:

$ mv ~/.android/adbkey ~/.android/adbkey.old
$ mv ~/.android/adbkey.pub ~/.android/adbkey.pub.old
$ adb kill-server
$ adb start-server

Question 26

I just had to follow these simple steps:

Remove the wire from laptop and phone.
Again attached the wire to my phone and laptop
Allowed debugging on the device.

And every thing started to work fine.

Question 27

I had the same message in two phones:

- Sony Xperia E
- Samsung Galaxy Core 2

both Android 4.4.2, and i solved it with these two steps:

1.- Updating my adb to 1.0.31, downloading the latest version of Android SDK from SDK Manager

You can check your adb version by typing

adb version

2.- Once the phone is plugged in USB Debugging mode, A message appears asking you to authorize this computer for debugging. You have to mark "Always allow this computer", and click on Allow.

Hope it helps.

Question 28

it's not may work for all situations but because i used a long cable my device doesnt connect properly and the message wont pop up change the cable may solve the problem

Question 29

I just try adb kill-server, it works for me:

PS C:\Users\languoguang> adb devices
List of devices attached
MKJ0117A19000186        unauthorized
PS C:\Users\languoguang> adb shell
error: device unauthorized.
This adb server's $ADB_VENDOR_KEYS is not set
Try 'adb kill-server' if that seems wrong.
Otherwise check for a confirmation dialog on your device.

kill and start adb server:

PS C:\Users\languoguang> adb kill-server
PS C:\Users\languoguang> adb start-server
* daemon not running; starting now at tcp:12345
* daemon started successfully
PS C:\Users\languoguang> adb devices
List of devices attached
MKJ0117A19000186        device

Question 30

Here's what I did that that brought the authorization prompt and made my device appear. I used a Samsung Galaxy s7 edge.

Enable developer mode and USB debugging on your device.
Revoke the USB debugging authorization
Plug your phone to computer via USB.
Drag notification panel and select "Software Installation" as shown in the image below
This will begin installing USB driver and the prompt for USB debugging authorization will show.