Dropbox sync problem

I am running 1.3.9 portable on Windows 10. I have imported about 2.3 GB of data from Evernote. The notes display fine in Joplin, and the attachments (images, PDF, Zip, etc.) are in the JoplinProfile\resources\ folder.

I followed directions to setup Dropbox sync. It seems to finish syncing, but all of the data is not there, in Dropbox. I see 1438 .md files in Apps\Joplin, and 11 files in Apps\Joplin.resource. The number of files does not increase on later syncs. The entire Apps\Joplin\ folder only totals 33.6 MB. It looks like none of my attachments are syncing.

I am not using encryption (yet). I get no error messages. The log shows no errors.

Update: I changed to File Sync and pointed to the existing Dropbox folder. The sync isn't done yet, but it is now syncing many more files than before.

I'll check it in the morning to see if the attachments are there. It looks like they will be.

It looks like syncing to the local file system, using the folder in Dropbox works correctly. I still don't know why using Dropbox sync didn't, but I'll now try the Android app, and see if I can sync everything to it.