Can t connect Nexus 4 to adb unauthorized

Question

I have a Nexus 4 with Android 4 3 and I am trying to connect the device to a computer with Windows 7 64bit   I installed the latest drivers and the latest adb version  I think I tried almost everything and I still get the following message   C  Program Files  x86  Android sdk platform-tools gt adb devices List of devices attached 007667324ccb229b        unauthorized   What can be the reason for this error

User · Answer

1   Delete    android adbkey on your desktop machine  2   Run command  adb kill-server   3   Run command  adb start-server   You should now be prompted to accept debug key

User · Answer

hange USB connection mode from MTP to Camera  for Nexus 7  or  possibly  to Mass Storage or something else  for other devices   This option is usually under Settings - gt  Storage  Then connect the device again  you ll get the authorization dialog   MTP has been known to interfere with USB debugging -- these two did not work together at all on majority of older devices  Nexus 7 and many newer devices do allow both to work alongside  but this particular issue suggests it s not all that smooth yet   Bonus -- checklist for when adb is not behaving well    adb kill-server followed by adb start-server  on device  Settings - gt  Developer Options - gt  USB Debugging -- switch off and on  Windows  Make sure you have the proper driver  your best bet is Universal Adb Driver by Koushik Dutta -- will handle any device   Windows  Try turning off all fancy on-the-fly anti-malware scanners firewalls  Linux  Make sure you have the proper UDEV rule in  etc udev rules d 51-android rules  again  universal solution  https   github com snowdream 51-android   Linux  Make sure everything under    android is owned by you  not root  and upvote this answer  restart device  yes  surprisingly  this is a valid measure  too   Obviously  replug cable  try different cable  different port  remove any extender cables

User · Answer

My resolution was running adb devices from the command prompt  pathed to the adb application  For example C  Android platform-tools adb devices   Running this command returned the following   daemon not running  starting it now on port 5037    daemon started successfully    I then saw the device listed as unauthorized  unplugges the USB  plugged back in and was prompted for the RSA fingerprint

User · Answer

I solved this problem without deleting any keys  Here s how    My device was connected to my computer via USB I made sure Eclipse and android device monitor weren t running   Typed at the commandline prompt  adb kill-server Typed at the commandline prompt  adb start-server After adb was restarted  I got a prompt on my device to authorize which I allowed

User · Answer

This kind of an old post and in most cases I think the answer that has been upvoted the most will work for people   In Lollipop on a GPE HTC M8 I was still having problems  The below steps worked for me    Go to Settings Tap on Storage Tap on 3 dots in the top right Tap on USB Computer Connection UNCHECK MTP UNCHECK PTP Back in your console  type adb devices   Now you should get the RSA popup on your phone

User · Answer

I think it has an error when the device tries to display the screen asking for permission  so it does not appear   This works for me  commands are given in the adb shell     rm  data misc adb adb keys  I sent the public key  adbkey pub in    android   from my computer to my device via email  Invoke stop adbd  cat adbkey pub  gt  gt   data misc adb adb keys  authorize myself   start adbd  restart adb with new keys

User · Answer

I was able to solve this one by following the steps listed here http   forum xda-developers com showthread php t 2247471  delete the computers adb key  rm  data misc adb adb key on device    I have no idea if in case of multiple authorized computers the additional keys are in a new line of the file or if they are in new files  I have only 1 computer    stop all adb processes  killall adb  in linuxoids and  taskkill  IM adb exe  in windows or simply the taskmanager in both   restart the phone  toggle usb debugging off and on  connect  use adb  click authorize

User · Answer

I had similar situation  Here is what I did   Try to check and uncheck the USB Debugging option in the device   if not working  try to unplug plug the USB   At some point  the device should show up a messagebox to ask you if you authorize the computer  After you click yes  the device is then authorized and the connection is hooked

User · Answer

For my Samsung S3  I had to go into Developer Options on the phone  untick the  USB debugging  checkbox  then re-tick it   Then the dialog will appear  asking if you want to allow USB Debugging   Once I d done this  the  adb devices  command no longer showed  unauthorized  as my device name    Several months later     Actually  the same was true for connecting my Galaxy Tab S device  and the menu options were in slightly different places with Android 4 4 2

User · Answer

I was facing same  issue  I found I was using a simple usb cable which was meant for only charge and not data copy  using good usb cable solved my problem

User · Answer

I was not getting the RSA fingerprint pop up on my phone    I had to delete the C  Users  lt userName gt   android adbkey and adbkey pub files and then do kill and restart of adb server   adb kill-server adb start-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

User · Answer

Similar to Flavio s answer  https   stackoverflow com a 18542792 1064996   it was something to do with the files in    android  on the host machine  not the phone    I didn t have    android adbkey  but I did have    android debug keystore and my whole    android directory was owned by root  I removed the keystore file and also changed ownership to me  sudo chown -R  USER    android   killed the adb server and plugged in my phone  and it worked   It was probably the ownership thing  Make sure you have read write permissions in    android

User · Answer

Use a different USB cable  Some cables may not have all pins connected or whatnot  and while they work for image transfer  the debugging adb does not work   The bottom line  I kid you not  A cable which works for my phone  adb works  does NOT work for my tablet - the device is always offline or unauthorized and tablet pops out no dialog  I tried multiple reboots  settings  I went berserk in the process and cursed the bloody Android  Then accidentally I plugged in the cable which came with the tablet and suddenly it worked  My fascination with Android is definitely gone  What a stupid piece of junk

User · Answer

It happened for me after my backup software changed the permission to my user directory   I opened it in  File Explorer  it prompted me to set permissions and it fixed the issue     FYI   Android has a special directory under   User  android   If you can t access it  it won t prompt you

User · Answer

When I turn off my Comodo Antivirus everything goes back normal  All other solutions suggested here went in vain  Somehow I figured out one solution   If you are using Comodo Antivirus  Version 6 3  For other versions search for similar options  the following solution would help you   Open Comodo   Tasks   Advanced Tasks   Open Advanced Settings   Security Settings   Firewall   Firewall Settings   Advanced   Filter loopback traffic  e g  127 x x x    1   Uncheck this  Filter loopback traffic  option  which prevents adb from normal working

User · Answer

I reinstalled the usb drivers and ensured that I was not using USB 3 0 port   I then closed out eclipse and killed and restarted adb   Was immediately prompted on phone to allow computer access   After accepting I restarted eclipse and now my Galaxy S3 shows up in device Device Manager

User · Answer

Had the same issues getting an authorization token on my Nexus 5 on Windows 8 1  I didn t have the latest adb driver installed - this is visible in device manager  Downloaded the latest ADB USB driver from Google here  http   developer android com sdk win-usb html  Updated the driver in device manager  however enable disable USB debugging and unplugging plugging USB still did not work  Finally the  adb kill-server  and  adb start-server  mentioned in other answers did the trick once the driver was updated

User · Answer

For me once I disabled MTP  in Settings Storage Menu MTP  I finally got the RSA prompt

User · Answer

Here is my version of the steps    Make sure adb is running In device go to Settings -  developer options -  Revoke USB debugging authorities Disconnect device In adb shell type   adb kill-server In adb shell type   adb start-server Connect device   if adb shell shows empty host name  restart device

User · Answer

Had the same issue  Not sure if these are the same steps for Windows as I m using an OS X device but you can try    Reboot your phone into recovery mode  Connect it to your computer  Open the terminal and type   cd    android adb push adbkey pub  data misc adb adb keys  All done  Just adb shell reboot and feel the power

User · Answer

I had to re-install my adb driver to snap out of this probelm  I had install  Universal Naked Driver  in an effort to recover my phone  I uninstalled that and re-installed the driver out of the android sdk

User · Answer

Make sure adb is up to date Make sure you are using the google usb drivers  http   developer android com tools extras oem-usb html Make sure your ANDROID SDK HOME environment variable is set to the correct path

User · Answer

Simply re-plugging did the trick for me     The permissions-dialog didn t show up the first time I plugged in the device  the second time it did and everything is fine now

User · Answer

Four easy steps    adb kill-server   adb start-server  replug the device  unlock it and accept the new key

User · Answer

After you ensure you have enabled USB debugging unlock your phone and plug it into your machine via USB  You will be then asked to authorize communication with the computer you have connected to  It will also show computers RSA key fingerprint     Accept it and you are good to go

User · Answer

If you are on adb over network  try to connect via USB instead or vice versa  This did the trick for me  After accepting it once it always works later on

[android] Can't connect Nexus 4 to adb: unauthorized

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