TIL how to fix a broken Joplin sync

I use Joplin   for all my note-taking as it’s open-source, markdown-based, and has decent Desktop and Android apps. I use note encryption and sync my notes via WebDAV with my remote Nextcloud instance.

Problem

After not syncing my notes for several weeks, I encountered a couple of errors both on my Desktop app and on my Android app. I don’t have access to the error message anymore, but the errors referred to files and file IDs that caused inconsistencies on the remote server, e.g. broken references:

f1231gdffgasd1asd2.md TypeError: Cannot read property 'type_ of null.

Solution

To solve the issue, I had to delete the offending file on the remote server. However, to not lose it, it’s best to make a local copy of the file’s content if it is present on one of your local devices.

First, I had to determine which file caused the issue, which is a bit harder here as filenames are encrypted. The easiest way to identify the note from the filename is to paste a local markdown reference into a new Joplin note like this:

[Note I am looking for](:/f1231gdffgasd1asd2)

and then click the link in the rendered note. This took me to the offending note.

Second, copy the content into a new note.

Third, I had to delete the file on the remote. I connected on my Mac to the remote WebDAV server via Finder. In Finder, Click on Go -> Connect to Server -> Add address: https://yourserveraddress.org/remote.php/webdav/joplin (look up the link in your Joplin settings), and authentificated with my nextlcloud credentials. Then I was able to search for the file f1231gdffgasd1asd2 and delete it.

The sync now succeeds.