I was working on my first short film for quite a long time and then tried exporting the project about 5 times to get the best file size/quality ratio. Some of the exports failed, but at last I got, what I had wanted. Now, a week later, I wanted to make some changes in the project and export the movie again, but when trying to open the project I get a error message "This project contained a sequence that could not be opened. No sequence preview preset file or codec could be associated with this sequence type." Then I tried opening other old projects and for all of them I get the same message.
*My trash has 4 "Recovered files" folders in it, with I-Frame Only MPEG.epr files. I am quite sure they (or their missing) are somehow causing the problem.