If Premiere Elements is open, quit the application.
Troubleshoot error while attaching media
PRE could freeze while performing operations such as playback, render, or export as a result of corrupt conformed data.
Sometimes, saved projects do not open properly because of media conforming errors. In that case, you might face issues while performing operations such as playback, render or export.
Projects use conformed data to optimize performance while editing. These are saved in the common media cache folder. If conformed data gets corrupted, it could lead to errors in the project.
Go to the following path and delete the folder named 'Common'.
Re-launch the application and open the project.
Wait till indexing and conforming are completed before performing playback or other operations.