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VideoSort uses python library GuessIt to analyze filenames. In a similar approach a scan-script can be written to generate dupe keys from nzb-filenames. There is no reason to make that as part of VideoSort. A separate script would be easier to write and maintain. If it's supposed to be used for RSS ...
All these questions are not directly related to nzbget but to the docker container. Here we develop NZBGet but don't do anything with docker. I personally don't know much about docker to give any advice at all. Try to find support forum for the container you use (googling for "nzbgetvpn" give severa...
You can try this: pause download via main round button; from history use command "Download remaining files" or "Retry failed articles" for the failed item; add the second nzb to queue; click on new nzb, then on button "Files" and delete unneeded files; select both nzbs in queue and use command "Merg...
Delete all from queue (move into history), then in history select items you want to download (click on first item, then shift+click on last to select range) and choose "Download again" via button "More" on toolbar.
The message means the download queue is corrupted. Someone has deleted files from QueueDir.
Make sure QueueDir is on local disk which is always attached.