When I open up some tabs on tuxguitar and try to play the tabs by clicking "Start", the program gives an error saying "MIDI System is Unavailable". However, when I make an edit somewhere in the tablature, it seems like that action somehow "forces" the MIDI system to boot up, because after doing that playing the MIDI track works. This only seems to work when I'm online, however. If I disconnect from the internet, the above workaround won't get the MIDI system to start up either.
Hi, that problem happen with OSS on some sound cards (OSS is used by java sound api ).
allmost times this error happen because you have 2 or more sound apps running at the same time. ( Note a messenger app, also play sounds )
See here for more info
http://www.tuxguitar.com.ar/tgwiki/doku.php?id=doc:error_midi_unavailable_linux
I suggest you use the alsa output, by installing a software synthesizer like "timidity" and select it on "Tools -> Settings : Sound"