Violet UK has been in development since the early 2000s and possibly earlier. A few songs and appearances have emerged from it, enough to convince fans that something may happen someday, and an album has been being hinted at since 2007 with a promo implying a new debut in 2013. No one with any knowledge of the project or of Yoshiki expects this to happen, really.
Limp Bizkit's Unquestionable Truth Part 2 was delayed then scrapped and Gold Cobra was recorded instead, now Part 2 has been resurrected with plans to release it as an EP.
Poe's third album.
The career of Andrew Eldritch of The Sisters Of Mercy fame: "We are working on an album, inter alia, but the matter of single releases is currently on hold..." and has been for thirteen years.
Sarah Mclachlan had two hiatuses that were over 6 years long, back-to-back.
Dr. Dre's third solo album, Detox. It is been in talks for most of the aughties, though the current state of hip hop makes the prospect much less exciting than when Chronic 2001 came out. Dr. Dre has been promising Detox since 2000. Between the list of artists Dre said would be on the album and the lame acts he's signed to Aftermath over the years (acts who, according to many critics, already took up far too much of 2001) it's obvious what the holdup is: the man's become a perfectionist and can't decide who to work with.
The only two artists he's been able to work with consistently are 50 Cent and Eminem, it seems unlikely that Detox will ever come out.
Eminem(from a song released in 2004): "Don't worry 'bout that Detox album, it's comin'! We gon' make Dre do it!"
The album had two well-received promo singles in 2011; the second, "I Need a Doctor", hit the top 5 and has been nominated for a Grammy. So of course we get announcements that a) neither song will be on the album if it's ever finished, and b) Dre's going on a hiatus from music altogether.
Not to mention "Helta Skelta" the LOOONG delayed collaboration between Dre and Ice Cube. We are also waiting for the "New" NWA album with Snoop Dogg replacing Eazy-E. Dre has a history of announcing albums and never delivering.
Anthony Rapp released a single solo album, Look Around, in 2000. After that, he claimed he was giving up solo work in favor of promoting his alternative/indie rock band Albinokid, and has promised they'll release an album since 2005. Several track listings have appeared on his MySpace, and he's mentioned songs he plans to include at the band's live performances, but the album hasn't appeared four years later. In fact, from lack of information on the band, it seems that they broke up.
Wintersun's next album, Time, is taking forever to be released, supposedly due to problems with the recording equipment. It slowly became a punchline akin to Duke Nukem Forever, although the band has performed new material (including a new 10-minute song) live. As of 2012, the band has said it's almost finished and has a release date, so expect to see this entry moved to Saved from Development Hell soon.
How soon is yet to be seen. While the first half has been released, the second half is being delayed for unknown reasons until... 2014!?
E Nomine's next album. It was stated that it would be out by 2008 but as of September 2009 there has been no news of any band activity.
MF DOOM's Swift & Changeable still hasn't seen the light of day after being announced a few years ago. (That's not even counting the countless records that got shelved by an uncaring or hostile label, like Large Professor's The LP, KMD's Black Bastards or Jay Dee/J Dilla's Pay Jay, all of which have since either leaked or been reissued six or so years after being recorded.)
The Black Star follow-up album.
Nicole Scherzinger's solo debut was to come out in 2008. However, work with the Pussycat Dolls and lousy single choices doomed it, and she's creating new material for an album that will allegedly be out...someday.
It was finally released in 2010, but only in Europe. There is no US release date for Killer Love.
One of the most inexplicable is probably Lil Jon's Crunk Rock, which began production in 2006 (anybody remember "Snap Yo Fingers"?) as a grandiose rock-rap crossover album. One label change, four years and an entirely new set of material later, it finally came out under the title "Rebirth"
Lykathea Aflame's/Lykathé's unnamed album (despite claims that it was at least 90% finished. News has also surfaced that drummer Tomás Corn has been forced to quit playing due to foot problems, leaving the album's fate up in the air).
Anthrax's Worship Music has been languishing for a good while, mostly due to the band's recent inability to keep a vocalist for more than a couple of years; since their last album they've had John Bush, then Joey Belladonna, then Dan Nelson, John Bush again, Joey Belladonna again...should be Dan Nelson's turn again next.
Indie band Havalina announced their sixth album, Pacific, in 2004. The recording got delayed because the bassist wanted to add the percussion of a library cart being hit, and it took months for him to arrange to record this (the library wouldn't let him borrow the cart). Then the bassist left, and Matt Wignall found a new bassist, renamed the band to Matt Death & The New Intellectuals, rerecorded two songs, and tweaked the track list of the album (renamed to Death on the Pacific). Matt Wignall has said that the album is finished, and that he plans to release it as a free download. That was back in 2008...
Tapeworm. The super-band was headed by Trent Reznor as a side-project to Nine Inch Nails. Lineup was made of musicians from A Perfect Circle and others bands in the same "music genre"... Nothing resulted. Except a song that A Perfect Circle played live once and used in their last album (The song being "Passive"). More info here.
Bone Thugs-n-Harmony's Uni5:The World's Enemy album. It went through a frustrating amount of delays and pushbacks. Originally scheduled for a 09 release but was perpetually pushed back to May of 2010.
The music industry is notorious when it comes to shelving or stalling albums by female pop artists. Unfortunately, female pop artists have the least creative control. Usually they have to fight over artistic direction and their own public image and style, thus sending their albums to development hell territory.
This is especially true for female Pop, R&B, and Rap artists, Adina Howard being among the most known examples. Her '97-'98 Fantasy Island record was shelved because she wanted to do more than just sexually explicit songs. It was eventually bootlegged and released to the streets. Funnily, the album was still rather overtly sexual, leading people to wonder just how much sexier her label wanted the album to be.
Female rap group Da 5 Footaz Lifetime album never saw the light of day either, despite press kits being available. Their album was suppose to have been released as far back as '96. It has since been released underground via bootleg.
Jojo's got her third album stuck in so much development hell she sued her record company and then proceeded to delay it to the "right time". She ended up releasing 2 mix-tapes ("Can't Take That Away From Me" and "Agape") because she does want to give her fans things and cares. All I Want Is Everything (the third album mentioned) was later retitled as "Jumping Trains" and then was retitled again.
Nas' collab with DJ Premier, announced back in 2006, hasn't had any other info released since, but supposedly it's still being worked on.
As of October 2013, Premier claims that project is still on, but they are waiting until after Nas releases his Life Is Good follow-up, which will complete his contract with Def Jam.
Country Music artist Jo Dee Messina was supposed to have released an album titled Unmistakable in 2008. After two chart singles (one of which was withdrawn because Messina apparently didn't like it), the album finally got pushed back further and further. By 2010, it was announced that it had mushroomed into a trilogy of albums, the first of which (Unmistakable: Love) was released in April 2010 with little fanfare. The other two were released in November to even less fanfare and no singles.
LeAnn Rimes' cover album Lady & Gentlemen. First announced in 2009; first single (a cover of John Anderson's "Swingin'") stalled at the bottom of the charts. The announced release date came and went. LeAnn tweeted that the album would see release later in 2010 with a bonus re-recording of her debut single "Blue". A non-cover single ("Crazy Women") dropped in 2011 but fell out of the 40 in the blink of an eye. Finally in mid-2011, another new single ("Give", also not a cover) cracked the charts and the album was finally released in 2011. Incidentally, Rimes and Messina are on the same label (Curb Records, a longtime house of Executive Meddling).
And a more extreme example from Curb is Amy Dalley, who put out seven singles between 2003 and 2007, but despite getting as high as #23 ("Men Don't Change"), none were deemed successful enough for an album launch. Most country music labels are satisfied if a new artist even breaks Top 40...
LaToya Jackson's Startin' Over began its production on November 2001, has had some singles released, but has no date for hitting shelves yet.
Mike Shinoda of Linkin Park fame started a solo rap project known as Fort Minor during the band's break between records in 2005 and fans have never missed a moment to inquire about a second album. Mike has said he would return to Fort Minor. Someday. (Though at this point one wonders if he was being honest as he is infamous for playing Trolling Creator with the fans and teasing them...)
Frontman Chester Bennington's solo group Dead by Sunrise released one album back in 2007, much like Mike, he has expressed interest in doing more solo work but for the time being is focusing all of his energy into Linkin Park.
The follow up to Australian plunderphonics collective The Avalanches' debut album Since I Left You has been in development hell for nearly a decade. Every so often, a member of the band claims its done and they're just clearing the samples (this being important, since they're a plunderphonics group that means almost all of their music is samples), but then nothing in heard for a few years. The latest estimation is late 2011/early 2012.
My Vitriol are another famous example. Their 2001 debut Finelines faced no success in the US due to Executive Meddling which caused exhausting touring that put them into a 4-year hiatus. Then they got back together and started recording and then scrapped an album's worth of material (except four tracks that appeared on an EP) after lukewarm fan reception. Since then the follow-up has left fans waiting over 10 years. The band has had no word on when or if the album will ever be completed.
Lindsay Lohan's third album Spirit In The Dark was first announced back in 2008, the single "Bossy" was released and was very successful on the dance charts, but production was halted as Lindsay had decided it wasn't feasible for her to work on both her acting and singing career at the same time, numerous release dates were announced but nothing ultimately came of them due to Lindsay's own inability to decide when to work on the album, though several tracks have been leaked on to the internet over the years. It's unknown just how far along in production "Spirit" is, the album getting released depends on Lindsay getting around to finishing it, when that'll ever happen is anybody's guess.
Delta Goodrem has this happen a lot, mostly by her own making, Her third self titled album spent four years in development (04-07), her fourth album (Child Of the Universe) took about 5 years, three rewrites and two break ups, to come out. Both times are self inflicted development hells of sorts.
Christina Aguilera usually takes four years between albums, averted with Lotus which was a 2 year job.
The Veronicas recording company pushed back their third album 4 times now.
After the release of The Beach Boys' critically acclaimed Pet Sounds, Brian Wilson immediately went to work on Smile, an album that he planned to be his magnum opus. Public interest in the album quickly rose with the preview single "Good Vibrations" in the fall of 1966, but Wilson's good fortune quickly took a turn for the worse due to a combination of a drug induced breakdown, his bandmates' unenthusiastic response to the project (which, depending on who you asked, ranged from mild confusion to outright hostility), and the "Heroes and Villains" single stiffing on the charts, which greatly affected Brian's confidence in the project. By May of 1967, Wilson shelved the project, more or less ending his role as the main creative force in the group. Some of its songs were re-recorded in often inferior versions for Smiley Smile (the originals were finally released officially on the 1993 box set Good Vibrations: Thirty Years of the Beach Boys), "Cabinessence"'s original recording was eventually released on 20/20 in 1969 and "Surf's Up" made it out on the eponymous 1971 album, in a patchwork form that included a new lead vocal by Carl Wilson recorded over the original 1966 backing track, and a heavily overdubbed second section using Brian's vocals and piano demo of the song. Meanwhile, the album would remain untouched (and bootlegged) for the next 37 years before Wilson decided to give it another shot. Smile was finally released as a solo album in 2004, with surprisingly positive reviews. In 2011, Capitol Records released The Smile Sessions, which includes a reconstructed version of the album using The Beach Boys' original recordings.
Leona Lewis had her album Glassheart pushed back by a year by her recording company. Her first two albums Spirit and Echo didn't have this problem. (It did eventually come out in October 2012.)
Vanessa Amorosi has dealt with recording company issues and getting someone behind her work twice. First with her Somewhere In The Real World album, which had trouble getting destributed.
The line-up of Van Halen which featured Gary Cherone of Extreme imploded after the critical and commercial failure of their sole studio album, Van Halen 3. Eddie Van Halen would go through drug and alcohol addictions, survive tongue cancer (he apparently still smokes cigarettes) and a divorce to longtime wife ValerieBertinelli. A reunion tour in 2004 with Sammy Hagar followed, on the heels of a two-disc anthology with two new "Van Hagar" recordings (similar to the failed reunion in 1996 with David Lee Roth for Greatest Hits AlbumBest Of Vol. 1, but the Roth reunion never happened), but Eddie's re-emerging alcoholism led to poor performances and Sammy's second departure, this time taking founding bassist Michael Anthony with him to form Chickenfoot. Eddie would sober up, rehire David Lee Roth, and begin a world tour with Eddie's son Wolfgang replacing Anthony. A Different Kind Of Truth, Van Halen's first new album in fifteen years, and its first with Roth since 1984, would be released to commercial and critical success in 2012.
Several songs Hayden Panettiere recorded during her time as a Hollywood Records artist have been heard on Disney compilations and on soundtrack albums (as well as in her movies, such as The Dust Factory and Tiger Cruise), and her first album was due to be released during her time on Heroes... but the release date was pushed back several times, and with her only official pop single (2008's "Wake Up Call") not having been a hit (and being an Old Shame of hers to boot) the album is unlikely to ever come out. Her efforts with Nashville have been a different story, however (including her first sort-of solo album).
Beastie Boys' Hot Sauce Committee (Part 1), Part 2 of which was actually released. The album was originally scheduled for September 15, 2009, but was frequently delayed by MCA's health problems, resulting in his 2012 death. (The songs that were scheduled for Part 1 ended up on Part 2, which was released in 2011.) The group managed to record again before MCA died, but it is not known if that material will ever be released.
Shirley Manson's solo album. She eventually completed one, but her label denied to release it for not being commercial enough. She admits that said album even had a funeral for it.
Kraftwerk has been teasing a new album since 2003. While long absences aren't uncommon for the band (for instance after 1991's The Mix they basically went missing for nearly a decade), the fact that in the time since their last album founding member Florian Schneider quit leaves this new album's fate uncertain.
Despite the success of the Blue Öyster Cult and their solid record of acclaimed albums, it still took the best part of twenty years for band Svengali Sandy Pearlman to get his pet project, Imaginos, off the ground. Even though individual tracks had appeared on the band's early LP's and were sound and well received, delays and stalling and indifference from record companies meant it was 1988 before Pearlman's supernatural concept LP saw the light of day. By then, only the Two Oyster Cult were left - two of the original lineup - and the record was scratchily completed by a gaggle of hopefuls and disinterested studio session musicians. It was not a hit and to this day, the new tracks from the album are never performed on stage.
Vocaloid CV04. Fans rejoiced when they learned that it was the fourth product in Crypton Future Media's "Character Vocal" series. Fans rejoiced further when it was announced that he would be a male voice instead of a female one. The few fans that heard the demos rejoiced even further when it was implied that YuukiKaji would supply the voice. The fans were incredibly annoyed when they realized that he was taking so dang long to be released and that they don't even know his real name. It's been about three years since his existence was made known and still nothing. And don't go searching for those demos either, they're long gone. Worse still, it's been announced that Vocaloid3 will be released this September and the CV series is in Vocaloid2. Unless CV04 is released soon or released with Vocaloid3, he may stay this way forever.
Sky Ferreira had been signed to Capitol Records since 2008, and hadn't released an album until 2013. Keep in mind that her debut set had been delayed at least three times; its original release date was January 2011, with additional planned releases in 2012 and 2013 that proved to be nonstarters. While she had released two EPs and a couple of singles over the five year period, nothing she had put out prior to the release of her debut album had made much of an impact, and she basically coasted on blog hype and random modeling gigs to keep her name out there.
James Wesley, a Country Music artist. He signed with Warner Bros. in 1999 and put out two singles under his real name of James Prosser, but the corresponding album was apparently scrapped. In 2010, he signed with Broken Bow Records, charting five singles between then and 2013. Although the second and third singles were Top 40 hits ("Real" at #22 and "Didn't I" at #24), the album still failed to see release.
In the late 1990s, country singer John Berry was supposed to put out Crazy for This Girl, but curtailed it a few weeks into its first single's run because he was having vocal cord troubles. After he healed up, he recorded Better Than a Biscuit, but exited his contract a week before it was supposed to be released.
Montgomery Gentry had this happen at the end of their tenure with Columbia Records in the late 2000s. They were supposed to do an album called Freedom, whose lead-off single was "Oughta Be More Songs About That". After the single failed, the label decided instead to release an EP, whose lead single was "While You're Still Young". But after that failed, the EP was shelved and they left the label.
Jessica Andrews was slated to release her fourth album for DreamWorks in 2005. Its singles went nowhere, and the closure of the label left her high and dry. She moved to Disney-owned Lyric Street Records and released a song titled "Everything", which also underperformed… and then got screwed over again when Lyric Street closed.
Jamie O'Neal had a hard time following up her first album, Shiver. "Every Little Thing" was supposed to be on an album titled On My Way to You, slated for a 2003 release but it flopped and she left Mercury Records in favor of Capitol. The change of label got three hits off Brave between 2004 and 2006, but "God Don't Make Mistakes" went nowhere, as did two singles released in 2008-09 on a small indie label.
Rebecca Lynn Howard had not one, not two, but three unreleased albums. The first was Laughter & Tears, which had two singles in "What a Shame" and "I Need a Vacation", and was never released due to underperformance of both singles. She then moved to Arista and released two cuts that also went nowhere (they would've been on an album called Alive and Well), then a song called "Soon" for a never-finished album on Show Dog-Universal Music. She finally put out No Rules on Saguaro Road in 2008.
Necrophagist have slowly been becoming a punchline much like Winter Sun and Duke Nukem Forever in regards to how long they have been taking to make a new album. Necrophagist have started work on the new album back in 2008, but as of March 2014 there still isn't any new info on the new album. Their last album, Epitaph came out in 2004.
Insane Clown Posse's side-project called Soopa Villainz, in which ICP and other Psychopathic artists portrayed comic book-type villains, has fallen into a seemingly infinite state of limbo. Their first album, "Furious," was released in 2005 to luke-warm response. (At the same time, Twiztid were meant to portray an equivalent group called Soopa Heroez, whose corresponding album never did see release.) Then, in 2006, the whole Soopa Villainz project suffered a rather large blow when former-Villainz member Esham released an album of SV's unreleased material as a free, download-only release without ICP's permission - and managed to get ICP in a heap of trouble over the scathing, appallingly homophobic track 'Slow Your Roll', which was more than likely presented out of its intended context.
ICP eventually planned on attempting to revive the Soopa Villainz project with a trio of releases - an expanded edition of "Furious," a new album titled "The Land of the Banned," and an EP of Soopa Heroez material. NONE of this ever appeared.
Speaking of ICP, the big boxed set of the first six Joker's Cards which has been discussed for months (since mid-2013) and still has yet to come out? Yeah... we'll likely keep waiting, too.
Bloodhound Gang notoriously took six years to follow up their major hit album "Hooray For Boobies" with the relative flop "Hefty Fine." The follow up to that (alternatively titled "Gettin' Laid On A School Bus" or "Fishin' For Hookers") has been 'forthcoming' for eight years now.
Space had a major case of this with their third album, Love You More Than Football. Originally scheduled for release in 1999, the release date was pushed back to 2000. In early 2000, a single, 'Diary Of A Wimp', was released, and a tracklisting appeared on the band's website. 'Gravity', which had been premiered on the Bad Days tour in 1998, was a potential next single (and is featured on one of the Greatest Hits albums, as is the title track). However, the album itself ended up being shelved due to clashes between the band and the record company. Fortunately, some fans managed to get bootlegs of the songs.
Country Music singer Clint Daniels had two albums canceled on two different labels: a self-titled effort for Arista in 1998 (although the lead single fell just outside the Top 40) and an unnamed second disc for Epic in 2003. After the second one, he gave up singing in favor of songwriting.