You're getting «ioctl(_fd, USBDEVFS_CLAIMINTERFACE, &interfaceNumber): Device or resource busy» or «Device is already used by another process» exception/message box right after you started the application. This clearly indicates that some other process is accessing MTP device right now.
You could do the following steps to find it:
- Open you console emulator (gnome-terminal, konsole, whatever) and type:
lsusb(sudo apt-get install usbutils if it did not start) and find your device in its output, for example
Bus 006 Device 070: ID 18d1:4ee2 Google Inc. Nexus 4 (debug)
- Start fuser
sudo fuser /dev/bus/usb/<BUS>/<DEVICE>(sudo apt-get install psmisc if it did not start) - It should output something like this:
/dev/bus/usb/006/070: 23253 24377(actually, there could be more of them after semicolon, like : 24377, 24378, …) so, 23253 and 24377 are the pids of the processes which opened your device. - So, finally run:
ps -x -q 23253
23253 ? Sl 0:00 /usr/local/bin/android-file-transfer
ps -x -q 24377
24377 ? Sl 21:14 adb -P 5037 fork-server server
Usually, adb is not offending process, because it uses another interface, so the /usr/local/bin/android-file-transfer is the one