Hi Stephanie,
When making your screen recordings, do you have the project file saved in a local directory somewhere in your computer, or do you have it saved on a network drive? Having your project saved on a network drive might cause some issues when saving your project, so we recommend saving your files locally instead.
You can also try doing a repair of your Storyline 360 installation if you find that all of your recordings are not being saved properly, and you already have your project file saved somewhere on your computer. If the issue persists, you can reach out to our support team by opening a case so we can take a closer look at what's happening.