Yesterday, I was literally exporting perfectly. Perfect videos. Around mid-day, I adjusted a few things in my sequence (cut video, adjusted sound levels, nothing drastic), and now Premiere is exporting files that are unreadable, unplayable, and unusually small. My estimated file size is 3.5 gigs, it exports a file just over 200mbs. It exports at the same speed as a 3.5gb file would (45mins on my system), but the files are so small and useless. I've tried reinstalling, no luck. My export settings:
H.264, 1920x1080 (1.0), 23.976fps, Progressive VBR, 1 pass, Target 32.00Mbps, Max 40.00 Mbps, AAC, 192 kHz, Stereo.
If nothing was wrong yesterday and there is something wrong today for no real reason, I'd recommend trashing (resetting) your preferences.
To restore trash preferences, press Alt (Windows) or Option (Mac OS) while the application is starting. You can release the Alt key or Option key when the splash screen appears.
See if that works.