adb error: protocol fault (status 48 54 54 50?!)

Issue

adb stopped working in both Android Studio and command line suddenly. I'm using powershell in Windows:

..sdk\platform-tools> .\adb.exe devices
List of devices attached
error: protocol fault (status 48 54 54 50?!)

I can't find that these status code mean anywhere, any help will be appreciated.

I'm using adb version 1.0.36

..sdk\platform-tools> .\adb.exe version
Android Debug Bridge version 1.0.36
Revision fd9e4d07b0f5-android

Solution

The status XX XX XX XX part of the adb's protocol fault error message is not really a "status". It is just a hex encoded content of the first 4 bytes of the response that adb got back when it tried to connect to a port (which it most likely assumed belonged to an emulator instance). Your reads 'HTTP' which suggests that you have a web server running on a non-standard (for a web server) port.

Use netstat -b command to find what it is and kill it.

Answered By - Alex P.