Android Studio - Device is connected but offline

Question

This is quite a common question  but none of the solutions appear to work for me  First time asker  so apologies if I get the conventions wrong   I am trying to connect my Galaxy S5 to my computer running Ubuntu 14 04 so I can do some android development  I have recently downloaded and installed Android Studio and the SDK and my device is detected when it s connected via USB but the device either appears as  unauthorized  or  offline   I know I should be expecting the RSA key prompt but this never appears   I have tried      Checking debugging was enabled   Running adb kill-server and adb devices   Restarting  the device  developer options  the machine    Simple unplugging and replugging the USB cable  Checking my adb version  it is 1 0 31    Trying different USB ports   Revoking USB debugging authorizations Toggling enabling ADB Integration from within Android Studio Connecting as PTP device and MTP device   I have tried it on a separate machine that runs fedora and this works fine with no issues  the promopt appears right away  Therefore I imagine it is not the USB cable that is faulty   Any ideas

User · Answer

Try these    Unplug and replug the USB cable  If it still doesn t work  unplug the USB cable  disable then enable USB debugging in the device settings  If the above two methods fail  reboot the device  If rebooting the device also fails  reboot Android Studio too  If reboot Android Studio still fail  try adb kill-server then adb start-server   Hope this helps

User · Answer

Try killing adb adb kill-serverthen disable usb debugging and then start adb by adb start-server then enable usb debugging and plug phone again and huh don t let phone sleep between process EDIT  There turned out to be a problem with my laptop s ADB RSA key  I m assuming my G3 was rejecting a bad key and disallowing my laptop to connect to it via ADB  ADB saves a key file in one of multiple places on a Windows computer  the first is in the location where adb exe is  C  android   the second is in the user s  gt profile  C  Users username  android   the third place is in the Windows system files  C  Windows System32 config systemprofile android   the file is  gt simply named  quot adbkey quot  with no extension  If there is no key file when ADB runs  it will generate one automatically  Mine was located in my user folder  C  Users username  android   All I had to do was delete the adbkey file  there was also a file named  quot adbkey pub quot  which  gt I deleted as well   restart the adb server in command prompt  adb start-server  and plug my phone in  I instantly received the RSA Fingerprint Key window on my  gt G3 allowing connection between the two devices  Then typing  quot adb devices quot  returned my phone s serial number followed by  quot device quot  showing it was available   gt I went back to the C  Users username  android  folder and sure enought there were new  quot adbkey quot  and  quot adbkey pub quot  files   got from XDA EDIT 2 TRY this steps too  Navigate to where  android is stored open  android and delete file named as adbkey and adbkey pub Start ADB then typeadb kill-serverand adb start-server

User · Answer

In my case  turned out that you need to be logged as owner of device to properly accept the USB debugging   Tried the  Disable and re-enable USB debugging on the phone  step but didn t get the RSA prompt on  normal  user  switched to owner and tried again and got it

User · Answer

I tried most of the things on this page and none of them worked for my Samsung S5  However  when I switched the cable to a USB-C type the problem seemed to be solved   until next time

User · Answer

My fix to this issue    Android settings Developer options Revoke USB debugging authorizations Replug in device and accept authorization as usual  Profit

User · Answer

If you are on windows and you encountered the same problem  try to kill the adb exe process from task manager and then try to run your app again

User · Answer

This problem is because you have used an old adb version and not support on your device  or you have more than one adb   The key is    make sure you have a latest adb executable on your SDK Make sure to run adb command from  SDK DIR platform-tools   because this should be the latest version  type command  which adb  to check  if u have more than one adb file  you can rename another one    in my case  on my Windows 7 i have one more adb on  C  Windows adb exe  and its an old version  so my adb command always run from that file  I fixed the problem by running adb form my sdk directory  SDK DIR platform-tools adb exe

User · Answer

A shorter cable did the trick      It turns out that the wire thickness used inside the cable impacts on the resistance of the cable assembly     this resistance causes energy loss inside the cable when an attached load draws a current  and causes a voltage drop which can reduce the voltage to the end device to a point where it is not possible to charge quickly or completely    http   goughlui com 2014 10 01 usb-cable-resistance-why-your-phonetablet-might-be-charging-slow

User · Answer

Change the USB cable      I can t explain this technically  however after a lot of trial and error  this what have worked for me

User · Answer

If your app doesn t manipulate WiFi connections - another slightly different solution  which bypasses USB issues entirely - enabling a wireless debugging connection - ADB over WiFi TCP IP

User · Answer

Try upgrade your Android SDK Platform as below steps    Run the SDK Manager Execute  Install packages      Restart the SDK Manager    I tried and it s ok for me   ref  link

User · Answer

In my case  same problem - that Nexus 5 is connected but with  offline  status  the problem was solved by  Invalidate caches and Restart  in Android Studio  Suppose that problem was in adb and restarting Android Studio causes to adb restart

User · Answer

I also recently had this problem and I solved it by rebooting Android Studio  But my friend had to have the original cable for his device  no other cables worked

User · Answer

Reboot the your mobile this will fix it

User · Answer

Earlier for almost 3hrs I did    I tried everything given in several sites and my android device never came online  when I was running adb kill-server and then adb-startserver the  Device File Explorer  on the right bottom of the android studio showed  Device is not online  DISCONNECTED      Here is how solve this    Revoked all USB debugging authorization on the device under  Develop options  And I added sudo to command  sudo adb kill-server  and then   sudo adb start-server   After this the message in  Device File Explorer  in android studio changed to  device is pending authentication please accept debugging session on the device   But no message appeared on the device  Tried stopping-restarting adb  connect reconnet usb cable  stop-start usb debugging but nothing worked  Went back to device and changed the device usb settings from usb charging to  PTP   and  restarted the Android studio  And  boom  the message appeared on the phone to accept the debugging session on device

User · Answer

To fix this  use USB2 instead of USB3

User · Answer

Change your USB Preferences to File Transfer if you use your smartphone to debug   There are several option     File Transfer    Choose this one     USB Tethering  MIDI  PTP  No Data Transfer

User · Answer

Restart adb by issuing these commands in cmd  adb kill-server to kill existing adb session  followed by adb start-server to start a new adb session Disable and re-enable USB debugging on the phone and accept RSA fingerprints if asked by phone Rebooting the phone if it still doesn t work    If all above don t solve your problem  you may try delete environment variable named  ANDROID SDK HOME   It really solved my problem  Hope it Help you

User · Answer

Download and Install your device driver manually through visiting manufacturer website like  Samsung micromax intex etc

User · Answer

I had this issue on a device with USB-C using a microUSB cable with a USB-C adapter  After switching to a USB-C cable without any adapter it worked  I only saw this issue on a LeEco

User · Answer

In my case the problem was that I used a USB extension cable  As soon as I plug the microUSB cable right into the PC the device has detected

User · Answer

You can try this    Go to tools enable adb integration and uncheck it  now check it and run again  Next time  android studio will restart adb and it may find your device

User · Answer

use this command   - gt  adb disconnect  - gt  adb connect  lt ip address for your mobile port number gt    Eg   adb connect 192 168 2 58 5555

User · Answer

On windows--  Launch your terminal from the platform-tools folder inside android sdk   Then use the following commands  adb kill server adb start server   it should work

User · Answer

Step 1  Turn off USB DEBUGGING in Developer Options  Step 2  Remove USB Cable  Step 3  Turn on USB Debugging This rests USB Configurations   Step 4  on Command Prompt enter adb kill-server and then adb start-server  Step 5  Connect the USB Cable  Step 6  Check Devices connected in Run in Android Studio you should be able to see your device listed   Step 7  If you want to continue running using the cable this would be good enough   If you want to do Wireless Debugging continue with below step   Step 8  type adb tcpip 5555  If no error is displayed remove USB Cable  Step 9  Look up IP Address of your phone from About abd then type adb connect xxx vvv b n your phone s IP   Step 10  Check in Devices in Android Studio again and you shud see you r device in List of devices  If yes

User · Answer

Could not get Samsung Note II  N7100  to connect   Step 1  Follow answer from user4847410 above  Next time you connect your phone it will come up with an authorisation message and you re in   Step 2  I also swapped my cable   Step 3  Check USB port as if you install on one particular port then another port may not be ok for you   Note  made two batch files   adb-fix bat  adb kill server adb start server pause   adb-devices bat  adb devices pause      -- voted for that correct answer but I don t have enough kudos so it was removed  --

User · Answer

You maybe having an older version of the ADB  Update the tools package and that should bring down the latest ADB

User · Answer

Besides the solution mentioned above  try to download Samsung s Android USB Driver for your platform  Here is a link to the Windows one   https   developer samsung com galaxy others android-usb-driver-for-windows

User · Answer

Disabling and Enabling the Developer options and debug mode on the Android phone settings fixed the issue

User · Answer

I had a long white cable   Just wouldnt stay connected  Switched to another  shorter  black cable and it works 100  of the time

[android-studio] Android Studio - Device is connected but 'offline'

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