I created a 13 minute movie in Elements 12, When I exported it as a .wmv file, I realized it was 27 minutes long, not sure how all that blank space got added onto the end, but I deleted the project as I thought I was done. There doesn't seem to be any way to just trim the useless end off of the movie and re-save it as the same file type. How in the world would someone do that without downloading suspicious trial software?
Premiere Elements 12 on what computer operating system? Have you updated 12 to 12.1 using an opened project's Help Menu/Updates. If not, please do so.
Several perks to that including getting rid of the text style issue that exists only in the Expert workspace of 12.
For you immediate question...
What does "....without downloading suspicious trial software?" have to do with any of this.
It is highly probably that there was debris after the end of the intended Timeline which needed cleaning up.
For your 13 minute Timeline that ended up a 27 minute wmv file....
1. If you had not deleted the project file....open the project file to the Expert workspace.
2. Open all the tracks and expand the Timeline with the -+ slider above the Timeline.
3. Press the End key of the computer keyboard and watch where the Timeline Indicator stops. At that area, likely the 27 minutes mark, inspect all the tracks for debris (clip slivers presenting a very thin black vertical lines scattered about the tracks or whole clips that got pushed to the right to get them out of the way and were forgotten about.
4. You repeat "3" until the Timeline Indicator stops at the end of the intended Timeline content.
What is stopping you from importing your 27 minute wmv into Premiere Elements, trimming off the excess, and importing it as your wmv file? Are you seeing degradation when you do that?
Please review and consider. To avoid similar issues in the future, please consider doing the "End Key test" before export. For what you described, Premiere Elements 11, 12/12.1, and 13/13.1 are the same.