The way I always like to work is to select raw clips from my footage, then applying all the effects I want to do on them, render and then fine tune the in and out points of the clips, to fit the music I set it to. In previous projects this worked and I could just slide the end and start points of the clips on my timeline without having to render again. But with my current project I can change the out point of my clip, but as soon as I slide the beginning of my clip I lose the preview file. This is a really ineffective way of working. I hope somebody knows a setting that will prevent this. My sequences are PAL 16:9 25 progressive and I use 50P (deinterlaced) PAL footage and some 25P After Effects compositions.
Thanks for the help!