locks up at 98% while coding AVCHD file

On Premier Elements 12.1 on a pc.  On larger projects that are around an hour of video it locks up at 98% completion on a 1920x1080 coding mp4.  It saves a video file that has a file size of 0 bytes that won't open.  It also leaves two files in the same folder -- what appears to be a temp ADTS audio file and a temp Mp4 video file.  I can open each file and see the coded video or listen to the audio, but these are separate files.  It appears that the coding process is failing near the end when the audio and video files should be combined into a final Mp4 video file.