Android adb “Unable to open sync connection!”

Question

I can run and debug my Android app on my phone just fine, most of the time. Then, seemingly randomly, when I try to run or debug my app from Eclipse, the Console in Eclipse

Answer 1

The solution is likely to run on your android phone (on local terminal or ssh terminal): $ stop adbd; start adb

I don't like overkill solutions like rebooting hte phone... and this is usually not needed under Linux. I experienced the same problem when connecting over Wifi, so USB is maybe not responsible at all. Reading the answer from user655489, I got the idea to run lsof, and then lsof | grep adbd | wc -l => I think I had over many sockets open with all FD from 0 to 1023 in use... how suspicious.

I ran killall adbd, then restarted adbd per How can I connect to Android with ADB over TCP? And the problem was gone.

The cause is that, at least when debugging and having to kill my non-working apps, that several of the sockets never get closed.