If you use Premiere Pro enough, you will run into issues, and the most frustrating issue of all can be when you have problems exporting a sequence, especially when you are on a deadline. This can be absolutely terrifying, and you need to get your sequence exported ASAP!
So I thought I would give you some things that have been known to work for me.
The first thing to try is to trash the current render of your timeline and re-render. If you have a rendered timeline and you go to export a sequence you can save time and sometimes export easier by selecting use renders.
You can see this select above in blue, USE PREVIEWS. When your sequence is rendered and things are going well, it will use your Previews to render and should greatly speed things up.
Still sometimes the renders can get screwed up so clean fresh renders are a first step.
A second thing to try is is if you are compressing to a different format than you are editing in, is to try to match the sequence settings.
Especially if you are using the Previews this can speed things up and with no cross compression make the video easier to export. You can then recompress using Media Encoder, which should go quickly. Sure it is an extra step, but if it gets a working sequence out, it is worth it.
Next if things are really bad and you can’t get the sequence to export at all, you should move the sequence to a new clean project.
You should make a new project and drag the Sequence over, which will bring just it and the associated media files.
Most of the files are even brought over organized as they previously were, though unfortunately the organization of the sequences has not come over. Still save this Project and export from this project. This might mean that there is corruption in your project file.
Sometimes I move all the files in a project into a new fresh project and it can solve some issues.
Earlier of my posts talked about trashing the preferences and that is another thing I would try.
Hopefully when you run into the problems of exporting a sequence these things can help, and hopefully they can help you.