i unclicked optimize storage option on my iCloud account on Mac by accident as my uploads stopped and it started to download items and I now can't stop the downloading does anyone know when the download is finished where these items will be stored?

Hello kpf96,

Thanks for your question. We're happy to help. "After you download a file, folder, movie, TV show, photo, email attachment, or video, Optimized Storage keeps it on your Mac until more storage space is needed." If you turn off Optimized Storage, your data will be stored both in iCloud and on your Mac.

This can help explain things as well if you enable Optimized Storage: How to download content from iCloud when using Optimized Storage

This should help explain things. Let us know if you have any questions.

Best,