I’m trying to export a video I edited, length around one hour and every time I try to open it and play it in the file it is in it won’t and it says that it can’t be opened and that it is probably in some unsupported format even though it is in mp4
Did you wait until the export job is done?
What did you change in Export settings? For example, if you change quality to 100% it can cause this.
Did you try to play the export result in Shotcut?