The Who live at Live Aid (partially lost concert footage; 1985)
Live Aid was a music festival aiming to raise relief money to help the 1984 famine in Ethiopia, featuring artists such as David Bowie, Elton John, Led Zeppelin, Paul McCartney and The Who. The event was poorly received for many reasons ranging from the performances themselves to how the money was used after the event, including some of the funds allegedly being siphoned by Mengistu Haile Mariam to support his army.
The festival also suffered from several technical issues, including a power failure in the middle of The Who's performance of "My Generation", resulting in the loss of both the video and main audio feeds for television viewers, though many US radio stations were still playing the concert using a lower quality mirror feed. This took several seconds to set up, however.
Due to the power failure, a large portion of the video as well as some audio from the concert was lost. Additionally, Bob Geldof, the organizer of the event, promised every band who came that the event would be a one-off event that wouldn't be released anywhere afterwards, although MTV decided to keep archives of the event to their ability. Additionally, a DVD of the event was released over a decade later, albeit with several hours missing. Because of this and the overall minimal attempts by other event broadcasters to archive the event (especially parts that had technical problems), the lost portions of this performance may be lost forever.