Server Version#: Version 1.41.7.9823
Player Version#: Version Android 2025.17.0 (966828405)
When attempting to download a file, the error “Unable to determine whether this item needs to be transcoded before downloading.” appears on the client.
In the log, “Streaming Resource: Cannot make a decision because either the file is unplayable or the client provided bad data” appears.
This CAN but doesn’t ALWAYS happen if the source file has been moved but the plex database still contains the previous path as a potential source for the file.
Plex is missing the logic to skip missing source files and find one that is not missing, but of course will work correctly if it happens to try a working path first.
Simply removing the source file path that no longer exists fixes the problem.
In my case, I had turned off trash collection and moved my server from windows to linux, leaving behind old windows paths. When I added the new linux paths to the library paths, the individual items retained their old, now missing, windows paths. This caused plex to be unable to download files, though it could, interestingly, still play them.
Even more interesting, I was able to transcode and download a particular piece of media at least once and only encountered the problem when I deleted the download, changed the quality, and tried to download the same media again. This means that which path plex tries to use is not very deterministic, or at least that something is happening behind the scenes to reorder which path is tried first.
Once the downloads were failing, I could still stream by pressing play, but when I went into the library via windows instead of android, the media in question had the red “missing” tag over it. When I clicked on it, I saw both the windows and linux file paths. Deleting the windows path caused the “missing” tag to vanish, and caused the android downloads to start working again.
