Only the writer files are unusable. They are also much larger than I remember.
To get a relevant answer, please, edit (see the gray link below your question, above this comment) your question to cite OS and LO version, how you open the files (double-click, menu open, start center, …), how they were created (are they old or recent?). Generally, give maximum number of technical facts because we aren’t above your shoulder to watch your screen.