A member of the german forum reports the following issue with the Flickr-Synchronization:
DOpus can't download Images containing german "Umlaute" like Ä,Ö,Ü in their names.
When trying to download such a picture simply nothing happens (no error message, no Download). When doing another Sync the file has vanished from the list.
The same thing happens when trying to download a file containing a " / " in it's comment.
The issue has been confirmed by another forum member.
I can't test this myself because I doesn't have a Flickr-Account.
They should report it to H&P or GPSoftware support. (H&P if they want to report it in German; GPSoftware if they want to report it in English.)
If follow-up information needs to be requested to reproduce the problem then it's better if the people with the information are in contact directly.
I created a Flickr account to reproduce this issue.
I don't have any problem to download images with Umlauts but their names are destroyed.
A picture with the name 001 Rügen.jpg is downloaded as 001 Rügen.jpg.
Rügenänö.jpg gets the very nice new name Rügenänö.jpg
I can't reproduce the issue with the " / " in the comment, which is not meant to be a comment in the Metadata but a comment to the picture at the Flickr-Site. I can hardly think how this could prevent DOpus from downloading a file.
Based on that, I'd say Flickr is UTF-8 encoding the filenames but Opus doesn't expect it and treats them as ASCII.
(Please report it if it hasn't been already.)
Done!