My ADB stopped working recently. All commands results in error: protocol fault (no status).
Follow trace.
adb devices
system/core/adb/adb.c::main():Handling commandline()
system/core/adb/adb_client.c::adb_query():adb_query: host:devices
system/core/adb/adb_client.c::_adb_connect():_adb_connect: host:version
system/core/adb/sysdeps_win32.c::socket_loopback_client():socket_loopback_client
: could not connect to tcp:5037
system/core/adb/adb_client.c::adb_connect():adb_connect: service host:devices
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
system/core/adb/adb_client.c::_adb_connect():_adb_connect: host:devices
system/core/adb/sysdeps_win32.c::socket_loopback_client():socket_loopback_client
: port 5037 type tcp => fd 101
system/core/adb/transport.c::writex():writex: fd=101 len=4: 30303063 000c
system/core/adb/transport.c::writex():writex: fd=101 len=12: 686f73743a646576696
36573 host:devices
system/core/adb/transport.c::readx():readx: fd=101 wanted=4
system/core/adb/sysdeps_win32.c::_socket_set_errno():_socket_set_errno: unhandle
d value 10054
system/core/adb/transport.c::readx():readx: fd=101 error 22: Invalid argument
system/core/adb/sysdeps_win32.c::adb_close():adb_close: 101(lo-client:5037)
system/core/adb/adb_client.c::adb_connect():adb_connect: return fd -1
error: protocol fault (no status)
I had the same issue and found the problem: Android Studio.
Open the Android Studio menu Tools -> Android and uncheck Enable ADB integration.
adb devices should work (you might need adb kill-server first).
Then you can re-enable ADB integration in Studio.