"In Search of the Lost Chord" was remastered into SACD in March 2006 and repackaged into a 2-CD Deluxe Edition. Although the other Moody Blues albums released in Deluxe Editions in 2006 featured their original quadrophonic mix (encoded as 5.1 surround sound), "In Search of the Lost Chord" had never been released in this format, and a new mix was not released until 2018 when a 5.1 mix was released as part of the 50th anniversary box set. In 2008, a remaster for single standard audio CD was issued with the nine bonus tracks.