Greyed-out tracks

Hi there everyone,

I use a lot of FX tracks in iMovie. Until recently everything was OK but, then a number of them as well as music tracks became greyed-out. I went in to iTunes and played them and suddenly they were once again accessible to use in iMovie.

Does anyone know why?

I have two macs sharing one iTunes library. Could this be a reason? Seems strange.

Thanks for any help.

PG Logo