The content of many notes was deleted, at least 30-50 pieces, and the connections between them also disappeared

[ariehen]

Hopefully this can help:

Intermittent data loss for current document

Yup, this sounds likely. iCloud Drive has a habit of resetting things during an OS update, so it could be the reason it was fine until you recently did a major OS update. edit: just for anyone else who comes along with the same issue → Set the vault folder to always be downloaded (if you are using macOS Sequoia or above) or turn off Optimize Mac Storage for the entire iCloud Drive. It should be fine after that, but keep an eye on those settings with any major macOS updates.

and the Optimize Mac Storage setting screen (in iCloud Drive’s Settings)

iCloud Sync Disappearing Files

For starters, make sure Optimize Mac Storage is disabled in the iCloud Drive settings. [Screenshot 2024-07-13 at 20.31.24] Obsidian doesn’t like files being removed randomly by iCloud Drive. It may be something else, but that’s something to check first.