Chrome DevTools Devices does not detect device when plugged in

On a Galaxy S7 and Windows 10 laptop, all I had to do whilst connected to the computer was change the USB connection mode to "Audio Source" (Phone Settings > Developer Options > USB Configuration).

This then immediately came up with the on-device prompt to allow the RSA key fingerprint. Then the dev tools on computer recognised my device.

Why this works I do not know, however it is by far the simplest of solutions, and without the need for installing unnecessary software.

I have also had some luck changing it to "MTP (Media Transfer Protocol)" mode too, but only on occasion.

Edit:

The MTP option no longer works for me.

In addition to Audio Source, setting the connection mode to MIDI also works. It is alot easier to change the connection mode by accessing it straight from the device's notification bar - Tap the "Transferring media files via USB" or the equivalent notification.

Using MIDI is probably the easiest of the two since it doesn't require going into several setting screens to access it.

To get the functionality up and running:

• Follow steps at https://developers.google.com/chrome-developer-tools/docs/remote-debugging
• Install Windows USB driver http://developer.samsung.com/android/tools-sdks/Samsung-Android-USB-Driver-for-Windows
• Install Android SDK http://developer.android.com/sdk/index.html
• Install Android SDK Platform-tools http://developer.android.com/sdk/installing/adding-packages.html (this step was blocked on corporate wifi so I installed the single ADB package it required https://forum.xda-developers.com/showthread.php?t=2317790)
• Use command prompt to run ADB, in cmd go to the install directory of the ADB tools and type:
• adb.exe (might need to start and stop ADB using adb kill-server and adb start-server)
• Connect phone and browse to about:inspect in Chrome on desktop, ensuring a Chrome browser is open on your device

Following the above steps I got the RSA key fingerprint prompt to accept then I saw my device in Chrome.

Definitely not as easy as I thought it would have been but at least it now works.

Update 24 February 2016

So I updated to Windows 10 and now have a Samsung Galaxy S5, devices running Chrome v48.0.2564.116 m and v48.0.2564.95 respectively. Followed the steps from the Google docs and...it didn't work again, no RSA key prompt. So I began to follow my steps as above and thought there had to be a faster way as the Android SDK was over 1GB download.

This time I tried:

• Follow steps at https://developers.google.com/chrome-developer-tools/docs/remote-debugging
• Install Windows USB driver http://developer.samsung.com/android/tools-sdks/Samsung-Andorid-USB-Driver-for-Windows (the PC alerted me saying it was already installed but I still did it anyway)
• Install the single ADB package required https://forum.xda-developers.com/showthread.php?t=2317790)
• Go to the ADB install folder which for me was C:\Program Files (x86)\Minimal ADB and Fastboot\
• Open command prompt and run adb devices (alternatively I could have run adb start-server but the prior gives a more informational response)

Now, with Chrome open on my phone and chrome://inspect/ open on my desktop I can see the inspect options.

Next problem: I need to repeat the same steps each time I reboot Windows. To solve that issue:

• Open a text editor and copy in "C:\Program Files (x86)\Minimal ADB and Fastboot\adb" devices
• Save that file as adb.bat in the Windows Startup folder located at C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp

Note that the file does NOT need to be called adb.bat as long as it is a .bat file. The command you copied into the file has the default install path which you may need to alter for your set up.

Now I have the Chrome Inspect feature working when I need it.

Bit thanks and shout out to all others who have contributed their answers to this question which helped guide me towards a useful update to my answer. Please give credit to other answers where you find they have helped you too.