Sony Vegas Pro 13 was released some 8 years ago and GoPro 11 (2022) uses a modern version of HEVC (H.265) for 4K/5.3K video. If you are recording UHD in your GoPro 11 (thus HEVC), then its HEVC codec is well beyond the capabilities of Vegas Pro 13.
Sony Vegas pro 13 won't open files shot with GoPro 11. How can I fix this?
@xxxALEXxxx I have a Hero 10 and have a setting for video compression of H264 + HEVC and if I select this it records 4K in H264 which my Sony Vegas Pro 13 handled fine. But 5.3K and slomo's are recorded in HEVC which it couldn't open. If the Hero 11 has the same setting and you're happy with 4K just try that for now. It's funny, I upgraded to V19 just because of the Hero 10 and for HEVC support, but now I'm so pleased I did for other reasons :)