Sync Error 4: The file doesn't exist

[rms]

Welcome to Scrivener and the Scrivener forum.

I’m not familiar with the video you mention. And I don’t quite understand your comment “…created projects (just titles) for my story ideas and linked my Dropbox to it.” Sounds like your Scrivener project not quite yet into Dropbox.

That being said to troubleshoot and perhaps re-setup your Scrivener projects in Dropbox to enable synching with Dropbox. See

Using Scrivener with Cloud-Sync Services / Cloud Syncing / Knowledge Base -...

I’d start first with getting macOS Scrivener synching with Dropbox first, then tackle iOS. Make sure you set Dropbox to enable offline and not online.

I keep my Scrivener projects in the folder ~/Dropbox/Scrivener.

Also see the coincident post just today from a L&L Scrivener Support Guru @kewms

Sync? Export?

Install the Dropbox software on both machines. On both machines, make sure it’s running, logged into the same account, and configured to “Make available offline” for the folder you plan to put your projects in. With Scrivener closed, use Finder/Windows Explorer to move the project into the Dropbox folder on Machine A. (“The project” is the entire .scriv folder including all subfolders.) Allow Dropbox to sync. Confirm that the project appears on Machine B. Make a small but visible change, and …