I can't open a Premiere Elements 14 project. I have created 4 other projects (which I can still open) with no problem. I am getting an error message of "An unknown error occurred while opening the project". I have restarted the computer, but still get the same error message. I am operating on Windows 10.
Do you recall moving, deleting, or renaming any of the files and folders that went into this project after the project was saved closed?
If the AutoSave feature was enabled during the running of the project, can you get any of this project's AutoSaves to open for you?
Reflecting, how is this project different the others - formats, duration, complexity, etc.?
Please review the Adobe document on troubleshooting damaged projects and determine if any of those suggestions work for you.
Please consider, give results, and then we can decide what next if still necessary.