After adding Virginia Madsen as a co-host during season 11 failed to boost slipping ratings, CBS canceled the series after only a two-season, 12-episode run on June 11, 1999.

Cosgrove-Meurer Productions maintains a website for the show, featuring popular accounts and ongoing cold cases (murder or missing persons), with a link to an online form should a viewer have information on an unsolved crime.

That same year, FilmRise acquired worldwide digital distribution rights to the series and announced its intent to release updated versions of its episodes.

[4] Between February and March 2019, FilmRise began posting digitally restored and re-edited episodes, hosted by Stack, on YouTube.

[13] Unsolved Mysteries used a documentary format to profile real-life mysteries[14] and featured re-enactments of unsolved crimes, missing persons cases, conspiracy theories and unexplained paranormal phenomena (alien abductions, ghosts, UFOs, and "secret history" theories).

The concept was created in a series of three specials produced by John Cosgrove and Terry-Dunn Meurer, which were pitched to NBC in 1985 and shown in 1986 with the title, "Missing... Have You Seen This Person?"

The pilot of what eventually became Unsolved Mysteries was a special that aired on NBC on January 20, 1987, with Raymond Burr as host/narrator.

Episodes released between 1995 and 1997 featured journalist Keely Shaye Smith and television host Lu Hanessian as correspondents in the show's "phone center", where they provided updates on previous stories as information for "special bulletin" segments.

A March 14, 1997, episode featured journalist Cathy Scott in the reenactment of rapper Tupac Shakur's 1996 unsolved murder.

The show was known for its eerie theme song composed by Michael Boyd and Gary Remal Malkin, and for Stack's grim presence and ominous narration.

One episode featured a video of an arsonist filming an unidentified house being burned down while he was giving strange commentary.

In 1992, NBC aired a short-lived dramatized court show spin-off program called Final Appeal: From the Files of Unsolved Mysteries, also hosted by Stack.

The premise of this program was to try to give the unjustly accused a final appeal for help, with the debut episode taking an in-depth look at the Jeffrey MacDonald case.

When CBS canceled its Block Party line-up in the spring of 1998, the network moved the show to its Friday 9:00 pm timeslot.

When the series returned for its abbreviated 11th season in the spring of 1999, Stack was joined by actress Virginia Madsen for hosting duties in an attempt to boost its female audience.

When the show was in active production, the toll free number was displayed on the bottom of the screen below the title logo at the end of each segment.

The existing segments were also edited to be shorter so the show could be expanded to present five cases in an hour rather than the four of the original series.

The series is being "refreshed" by Stranger Things executive producer Shawn Levy and his company 21 Laps Entertainment along with Cosgrove-Meurer Productions and Netflix.

[25] On September 1, 2021, Netflix formally announced that it had ordered an additional season of the series set to launch in the summer of 2022.

In 1992, Unsolved Mysteries filmed in Texas and cast Matthew McConaughey to play a murder victim.

[27] Cheryl Hines, Stephnie Weir, Bill Moseley, Ned Bellamy, Scott Wilkinson, Daniel Dae Kim, David Ramsey, Diane Franklin, Steve Reevis, Donna Mitchell and Taran Killam also appeared on the program before receiving more notable work in Hollywood.

In 2018, Terror Vision Records made a deal with program creator John Cosgrove to release the show's official score on vinyl, Unsolved Mysteries: Ghosts/Hauntings/The Unexplained.

[41] On October 21, 2020, it was announced that Cosgrove/Meurer Productions had struck a deal with Entercom-owned Cadence13 for an official Unsolved Mysteries weekly podcast.

[43] A 35th anniversary documentary special titled, Unsolved Mysteries: Behind the Legacy, was formally announced on September 7, 2023.