Beginner Question - Projects across Libraries

I am working with a library in a sparse image that has all my clips in it, but creating a project in a library that is on my fast external drive. Every time I use something from the sparse image I get a warning. I am not sure I completely understand it.

My hope is that my project would run/work without the sparse image library being available. If it does, I am just fine with the warning. If I don't understand and the project will require the sparse image to be available, I'd appreciate someone letting me know that is how things work, and anyway around the problem.

The project has to be in the library you're working. If the project is in another library, on another drive, the media is copied from one library to the other when it is added to the project.

Thank you for the explanation.