Editing red footage

[Amoscall]

So I dumped my footage into FCP after my shoot, labled etc. Now i'm editing and all was going good until I lined up some clips and the become grey in my canvas. I'm not sure why. I am running FCP 6
could it be a 4k issue? and if so should I convert it using rushes?

[Ian Laurie]

might be a quicktime issue. close final cut, quit quicktime, then restart final cut. I had a similar issue in the past and it seemed to be the crashing of the quicktime plug in.