We are working in a studio full of Macs, some on CS4 and some on CS5.5, we have had a problem occur in the last week.
We are saving IDML files on CS5.5 and trying to open them up on one of our Macs running CS4 and it starts to open, stalls then crashes completely. We have tried opening it on another mac using CS4 and we have no problems at all.
The mac we are having the crashing issues with hasn't had any updates in the last week and we haven't had any other problems.
Maybe a bad font. But if you post your crash report on Pastebin.com, NOT HERE, then put a link here, someone may be able to interpret it and see the cause.