Premiere Pro won't allow me to select the files for missing media

I save Premiere Pro Projects using Project Manager to an Easy Store external hard drive. When I try to open projects from 2-3 years ago, Premiere Pro searches every single folder in my MacBook and then tells me the file cannot be located, yet I'm sitting here looking at the files I need in the folder where I saved the project in my Easy Store drive. I tried selecting the Easy Store drive as the search location, but Premiere Pro won't allow me to select it even though it's an option in the locate File window. Why is this so hard? What did I not do right? I have a sinking feeling that the projects I've saved (as instructed by Adobe) are now unusable. I've got 40 to 50 of them that I cannot open because the files cannot be located. The files I know are there.