Sometimes a band member just wants to do their own musical thing. There aren't any problems in the band (at least, not enough to justify a breakup). Instead, this lone member decides to take a break from the band, if it's active, or just get out on their own during a hiatus and write, record, and/or compose music and perhaps release an album or an EP when all's said and done.
Contrast Breakup Breakout, where a band member finds success going solo AFTER the band... well, breaks up.
KISS did this, with all four members releasing solo albums at the same time.
Fictional example: In That Thing You Do!, Guy Patterson (the drummer) works on his jazz chops during the band's big tour.
Brandon Flowers and Ronnie Vanucci of The Killers both released solo albums in the last few years, but the band are still together and working on a new album.
Thom Yorke, Jonny Greenwood, and Phil Selway of Radiohead—the frontman, lead guitarist/keyboardist, and drummer, respectively—have all released solo work during the band's time together.
Thom's got the electronic The Eraser and the Spitting Feathers EP under his belt, as well as remixes of other artists and a contribution to the Twilight soundtrack.
Phil has released both an album (Familial) and an EP (Running Blind).
Jonsi of Sigur Rós has released Go, a distinctly more electronic-sounding album than his band's usual Post-Rock output.
After the release of Boston's second album, Don't Look Back, songwriter and lead guitarist Tom Sholz got mired in legal conflicts with the band's producers, causing a long delay in the production of their third album. In the meantime, backup guitarist Barry Goudreau, along with singer Brad Delp, recorded a solo album titled Barry Goudreau. Goudreau later went on to split away from the group, forming his own band, Orion The Hunter (which featured the future Boston vocalist Fran Cosmo, and backup vocals from Brad Delp), and, later, with Delp, RTZ.
Julian Casablancas of The Strokes has released a solo album.
Davey Havok and Jade Puget of AFI started a side project called Blaqk Audio, releasing an album called Cex Cells.
Guitarist Adam Dutkiewicz of Killswitch Engage started a solo project (with former Killswitch Engage vocalist Jesse Leach) called Times of Grace.
The list of side projects various Converge members have been involved in is as long as your arm.
Graham Coxon of blur fame wrote and released his own albums while the band was still together, and has continued his solo career post-breakup.
For the Beach Boys, Dennis Wilson was the first of the classic 6-man line-up to release a solo album, with the lost classic "Pacific Ocean Blue" in 1977, which is still held in high regard. He attempted to create a second solo album, called Bambu, but as Dennis's personal life was going downhill, the album was never completed by the time he drowned in 1983.
Bruce Johnston and David Marks each pre-dated Dennis with their own solo albums. But Bruce made two solo albums before he joined the Beach Boys in 1965. The first is a surprising good live album "Surfers' Pajama Party" in 1962, followed by "Surfin' Round The World" in 1963. Bruce made his third and final solo album, "Going Public" in 1977, 5 years after he left the Beach Boys (in 1972), and around a year before he returned (in 1978-1979).
David Marks formed the band David Marks And The Marksmen after he left the Beach Boys, but they only released a compilation album decades after they broke up. He was also a member of the late-60's Psychedelic Rock band The Moon and with them created the albums "Without Earth" in 1968, and "The Moon" in 1969. His first proper solo album came much later, with "Work Tapes" in 1992. This was followed by "Something Funny Goin' On" in 2003, and "I Think About You Often" in 2006.
Mike Shinoda of Linkin Park had the side project Fort Minor.
Around 1977-8, all the members of Yes released solo albums.
Bill Wyman was the first Rolling Stone to release a proper solo album, with the brilliant and underrated "Monkey Grip" in 1974. This was followed by the average "Stone Alone" in 1976, the great but dated "Bill Wyman" in 1982, and finally the awful "Stuff" in 1992 (immediately prior to his departure from the Stones). He was also the only Stone to have a major solo hit, with "(Si, Si) Je Suis un Rockstar" in 1981, as well as the minor hits "A New Fashion" and "Come Back Suzanne" in 1982. His first solo single was "In Another Land" from the Stones album "Their Satanic Majesties Request" in 1967. He also composed and contributed to the soundtracks for the films "Green Ice", "Phenomena" and "Terror At The Opera".
Bill also formed the short-lived band Willie And The Poor Boys in the mid-80's, and created a self-titled album which had many high-profile musicians, as well as Charlie Watts.
Both Mick Jagger and Keith Richards have also released solo albums from the 80's onwards. Mick's solo albums are "She's The Boss" in 1985, "Primitive Cool" in 1987, "Wandering Spirit" in 1993, "Goddess In The Doorway" in 2001, and the soundtrack to the film "Alfie" in 2004. He also contributed to the soundtracks of "Performance" and "Ned Kelly", with "Memo From Turner" being his first solo single in 1970. However, his solo career (especially early on) nearly destroyed the Rolling Stones, and has helped destroy Mick and Keith's friendship.
Keith Richards also created two solo albums, "Talk Is Cheap" in 1988 and "Main Offender" in 1992, and his earliest solo single, a cover of Chuck Berry's "Run Rudolph Run" dates back to 1978.
Ronnie Wood's solo career started in 1974 with "I've Got My Own Album To Do" (Bill Wyman's "Monkey Grip" pre-dates it by a few months). This was followed by "Now Look" in 1975, a soundtrack to the movie "Mahoney's Last Stand" with Ronnie Lane in 1976, "Gimme Some Neck" in 1979, "1234" in 1981, "Slide On This" in 1992, "Not For Beginners" in 2001, and "I Feel Like Playing" in 2010.
Mick Taylor also had two solo albums after he left the Rolling Stones, with "Mick Taylor" in 1979, and "A Stone's Throw" in 2000.
Also, Brian Jones wrote the soundtrack to the film "A Degree Of Murder" in 1967, and produced the album "Brian Jones Presents The Pipes Of Pan At Joujouka", posthumously released in 1971.
Charlie Watts also released some solo work, which is of a very different style (Jazz) than the Rolling Stones normally play.
Almost all the members of the supergroup Crosby, Stills, Nash and Young released solo albums during the band's tenure.
Guitarist Jerry Garcia released several solo albums, and also had several side projects, including Saunders and Garcia (rock and funk), Old and In the Way (bluegrass), and Wales and Garcia (free jazz).
Guitarist Bob Weir put out a solo album, and also had a couple of side-project bands that released albums.
Bassist Phil Lesh had a solo album of experimental electronica featuring a wide variety of guests from several San Francisco bands. (His band, Phil and Friends, didn't form till after the Dead broke up, though, and thus does not qualify.)
Drummer Micky Hart had a couple of albums with his band Rolling Thunder.
Eddie Vedder of Pearl Jam did the soundtrack for the film Into The Wild while Pearl Jam were still together. He also released a solo Ukulele album.
Phil Collins started his highly successful solo career in 1981. Around the same time, Genesis grew more popular, too, with Collins still as their drummer and lead singer. That way, it was pretty much impossible to avoid his music in The Eighties. It wasn't until the late Nineties that Collins left Genesis.
Also, guitarist/bassist Mike Rutherford recorded two solo albums before forming his own Solo Side Project, Mike + The Mechanics.
Not to mention Genesis' former and gone-for-good lead singer Peter Gabriel.
Steve Hackett's first solo album, Voyage of the Acolyte, was recorded before he formally left Genesis.
Andrew Horowitz of Tally Hall is "edu" when left to his own devices. He released his debut album only on cassette tape in 2012.
Rob Cantor also began a solo career in 2012.
Five hats means that five tropers think it is ready to publish.
You are saying that you think this draft is ready to be published. That means the description is not ambiguous,
it doesn't duplicate an existing trope, there are at least three examples, and the title makes sense.
Is that what you meant to do?
You are saying this draft has a ready-to-publish hat it does not deserve and you are taking it back.