we need more info to being able to help, like a screenshot of the exact message.
Also, please tell us where exactly you stored your project (there have been several cases where people stored their projects in a protected area where they never should have been placed)
However, that usually happens if something went wrong with the files or the directory itself, usually when a background program like folder access control or antivirus interferes,
Also, please confirm that you're talking about VX Ace like your profile says - different Makers have different results.