Let me provide you some information:
ActivePresenter stores large audio/video files in an external folder named in the PROJECT_FILE_files stored in the same folder with the project file (.approj)
So if you copy, rename, move, or share the project file, please do the same with that folder too.
If you moved the project file then you can move it back to its original location.
Besides, you can delete irrelevant/unnecessary files or change the project location to another drive to get more space.