I saw many people having this kind of problems in the past, but none with the latest version (1.05).
So here is my problem. My Arduino system has been running fine for months on my Mac (OSX 10.9.2)... then I started to get "Serial port '/dev/tty.usbmodem411' already in use" errors when trying to compile or view trace.
When it happens, there is no solution other than plugging on a different USB port (which quickly becomes unusable as well), then rebooting (which is really painful!!!).
If I check with lsof | grep modem, I get absolutely no result, and when it happens, I'm sure that no other program is using the serial port... So I suspect it's a bug in the IDE.
Any suggestion to solve this problem ? Thanks!