Aggressive antivirus (Avast, Bitdefender, Norton) or a firewall can intercept HTTP range requests – which look suspicious because they ask for partial data. When a segment request is blocked or altered, JDownloader throws the error.
: Corrupted core files or failed updates within JDownloader can lead to erratic plugin behavior. Workarond to "PluginException: Segment:XXX not loaded" #16 jdownloader segment not loaded new
If JDownloader runs out of RAM, segments fail to load. Aggressive antivirus (Avast