I'm trying to speed up a 1 minute Quicktime clip to 400% and I get this message. Same with 300% or 700% yet I can speed it up by 120%, I can slow it down and I was able to speed it to 400% last time I was here. (I'm filling in a MEDIA OFFLINE clip that was unrecoverable following a hard drive failure).

Has anyone else had this issue? It's frustrating because I can't continue with this project unless FCP cooperates with me.

Copy the file and try the retiming with the copy.