Projects from old GarageBand completely changed when opened in latest GarageBand

I bought a new Macbook Pro and opened my GarageBand Projects from the external hard drive I use, and the instrumental sounds are completely changed to new sounds. If I reopen on the old macbook the projects all sound correct. What is causing this change? Is there a way to get the new GarageBand to open my projects as they were saved? NOTE: when I try to open a project in the new GarageBand It forces me to save the project to a location, but won't just open it as usual. PS typing into this forum on iPad is a nightmare, so please forgive the short description and any typos. Thank you guys so much for any help. -troy