Garageband won't save

I opened garageband this morning to write down a song that came to me, and it wouldn't let me save or save as. It didn't give any "failure to save" error messages, it just looked like it was saving and then the icon never stopped being transparent. And when I click save as nothing happens, no window pops up. When I selected new project and asked me if I wanted to save before closing, it didn't save (but thankfully didn't close either), and I could export the song to itunes so I at least have the melody and chords for future reference, but I don't know what's going on. Any idea why this is happening?