I'm editing a sequence at 24fps but a couple of scenes were shot by mistake at 60fps. I have been working with this material for three years without issue. I did not modify the clips but they played fine in the 24fps timeline all this time. All of a sudden now I'm getting tons of error messages when opening the project. The material shows up in the project window and timeline as if it has audio but there is no waveform and no audio. I tried to import the camera files fresh and same problem. I opened up old projects and had the same issue. I did go into the project and modified some of the clips (Modify-Interpret) but that didn't help either.