Rush source files aren't openly accessible to the Creative Cloud user in their desktop/mobile apps, although your files are stored there. I have had a few instances where some VERY large video files took several hours to sync from my iPad to the desktop, so if you have a LOT of content in the project, consider removing any UNUSED media from the project and letting the sequence FULLY SYNC (no blue loading circle in the upper right corner) before trying to open on the desktop, and then make sure the project has FULLY SYNCED on the desktop before attempting to edit there.
Hope this helps!
Hope this helps! Make sure to press "✔ Correct Answer" on this post if this answers your question. Happy Creating! Anissa • @anissat