I also got this. Standard installation of Ubuntu 12.04. The file is indeed only created on shutdown. I logged in and out but the file wasn't there. Once I shut down my cumputer and started it again it was there. The timestamp matches exactly the shutdown time. (I waited a few minutes before starting it again.)
$ ls -al | grep goutputstream
-rw------- 1 me me 110 jun 13 19:49 .goutputstream-4USLFW
$ file .goutputstream-4USLFW
.goutputstream-4USLFW: X11 Xauthority data
I also got this. Standard installation of Ubuntu 12.04. The file is indeed only created on shutdown. I logged in and out but the file wasn't there. Once I shut down my cumputer and started it again it was there. The timestamp matches exactly the shutdown time. (I waited a few minutes before starting it again.)
$ ls -al | grep goutputstream 4USLFW 4USLFW 4USLFW: X11 Xauthority data
-rw------- 1 me me 110 jun 13 19:49 .goutputstream-
$ file .goutputstream-
.goutputstream-