Error message in Scrivener; cannot read an external sync RTF file.

I was a little concerned when I exited Scrivener: it gave me a message that it could not parse the RTF in an external sync file.
This was on the automatic sync to an external folder (I sync on closing Scrivener). I’ve attached the file it said it could not parse. Not sure why it couldn’t deal with it.

On exit again, I didn’t see the error again, so I’m assuming it was a one-time error (perhaps a Windows issue, though not sure what), but the error itself concerns me. I had changed that particular document (removed 4 words and added 1). What if it had lost thousands of words by updating from an outdated sync file that it didn’t write because it had issues?

On inspection, before and after update, there seems to be no problem with the RTF in the file (I copied it to a separate filename in a separate directory), but what couldn’t Scrivener parse?

I don’t sync to cloud at all.
ERROR 62 sync file Sanai 02a.txt (528 Bytes)

Has this happened again since you wrote in?

As far as I know, the “cannot parse RTF file” error isn’t harmful to your data - the file is still in your project and contains all the text. I know way back there was a bug in Scrivener 1 in which the program that tells Scrivener that the project files are safe to load crashed before it completed, which caused the error. But since we’re not seeing any other reports of this, it was probably an isolated incident and nothing to worry about.

Happened again. Last time I exited Scrivener, Scrivener showed that same error about not being able to parse a particular file in an External folder. This folder is my sync folder, and I had just, that session, made a number of changes to my project (added subdividing folders, rearranged a few things, et cetera). And there’s a reason why it couldn’t parse that file: it wasn’t there (file 17 in external sync folder for this project is missing):

So just a few minutes ago, I started up Scrivener, and I get another error:

Now, I knew better than to click OK, because I don’t mess with my External Sync folders outside of Scrivener. So I knew any changes were a result of Scrivener error, and thus syncing the project with the Folder contents was a bad idea.

There’s a bug here, and I’m not entirely sure what it is. I have sync to External folder set up, this way:

So, when I close a project, it syncs to an external folder. An “error in parsing” means, here, there was a problem writing the file (it’s not there) (not sure what the problem was). The document that should have been written as #17 is present in the project. And, applying “sync to External Folder now”, just now, solved the issue. But why is Scrivener doing this? I don’t sync anything to cloud. So far as I know, nothing else is doing anything when I shut down Scrivener or close projects.

The External Sync is meant specifically to make it possible to edit the text in a Scrivener project with an external editor.