Frankie Valli still performs with a group he calls the 4 Seasons, but none of the original 4 Seasons has been with him in years.
Styx effectively has no original members with the band.
Original bassist Chuck Panozzo is still affiliated with the band, and plays with them live on occasion, but he’s largely retired, due to health issues.
Guitarist James Young wasn’t in the original band’s line-up (when they went by “Tradewinds”, then “TW4”), though he had joined by the time they changed their name to Styx in 1972.
The original Judas Priest formed in 1969 with Al Atkins (vocals), John Perry (guitar), Bruno Stapenhill (bass) and John Partridge (drums). Within a year the band broke up, and Atkins joined another group called “Freight” which included K.K. Downing (guitar), Ian Hill (bass) and John Ellis (drums). Atkins suggested they change their named to Judas Priest, and they agreed. A few years later, with the struggling band’s fortunes fading, Atkins quit and was replaced by Rob Halford. Several songs on Priest’s first two records were written by Atkins.
When the Swedish death metal band Opeth formed in 1990, the lineup included vocalist David Isberg, plus three other guys (whose full names are lost to the mists of time…) Later that year, Isberg hired a new bass player named Mikael Åkerfeldt – however, he neglected to tell the rest of the band, which lead to a giant argument causing everyone (except David & Mikael) to quit. They hired a bunch of new members, but Isberg also quit by '91, while Åkerfeldt remains the most constant and visible member of the group.
So in both of these instances, arguably, all “original” members had left before they even started recording records. 
I brought it up in the last thread, but Napalm Death.
By the second side of their debut album, there were no original members left (both sides had the same drummer, but he wasn’t the original drummer).
Related:
We went to see the Ink Spots maybe 10 years ago at Cain Park in Cleveland Heights. They introduced themselves individually and acknowledged that of course they were not the original group, but gave each member’s provenance, if you will, and connections to the originals and all the other work they had done. It was stunning. Something like 275 years of jazz history there before us.
The Glenn Miller Orchestra is still touring…
The King’s Singers – an a capella group – was founded in 1968 and still tours and records.
This suggests an interesting question (well, it’s interesting to me, at least!). How far back in a band’s history do you go in counting original members, and in considering it the same band?
The band that eventually became The Beatles, for example, started as the skiffle group The Quarrymen, whose original line-up (according to Wikipedia) consisted of John Lennon, Eric Griffiths, Pete Shotton, Len Garry, and Rod Davis. Paul and George came along later, Ringo much later.
Arguably, when Paul, George, and Ringo reunited to record “Free as a Bird” and “Real Love” for the Beatles Anthology, you could say that The Beatles had no original members left at that point!
An ersatz version of Fleetwood Mac toured briefly in 1974.
I think there’s a version of the Trapp Family Singers that’s Maria and Georg’s grandchildren, and they just made an album with Pink Martini.
Fairport Convention had no original members from 1971 through 1976, when Simon Nicol rejoined. Dave Swarbrick and Dave Pegg, who had joined on the fourth and fifth Fairport albums respectively, kept the band alive through the seventies with an ever-changing lineup.
When Mike Ratledge quit Soft Machine in 1976, he left John Marshall, who had joined halfway through the recording of the band’s fifth album, as the longest-serving member. (Not counting Roy Babbington, who had guested with the band in 1971, but didn’t join until two years later.)
Trivia note: Ric Sanders has been a member of both of the above–extremely different–bands.
IMHO if they had a completely different name, they don’t count as the same band.
I haven’t decided what the deadline for joining a band to be considered an “original member” should be. At the earliest, it’s when the band first performs publicly. At the latest, it’s when they make their first professionally recorded album. (So, for example, Ringo would qualify as an “original member” of the Beatles by some definitions but not others.)
If you had a ship, which over time had had every single board in it replaced, is it still the same ship? If no, how many boards would have to have stayed original? One? Half the ship? What exactly makes it the same ship or not?
I forget which philosopher to attribute this to, but I’m sure someone here will tell me.
^ Or Lincoln’s axe?
The really unexpected thing is, in looking up the original members of The Quarrymen, I found that those original members (minus Lennon, of course) reunited in 1997, and have been performing as “The Quarrymen” ever since. The Wikipedia article lists the current lineup, and in the “Former Members” section, includes John, Paul, George, and Stu Sutcliffe. But not Pete Best or Ringo, because by the time they joined, the band was no longer called The Quarrymen.
Not really on topic, I suppose, but I found that amusing.
Aren’t there a number of Motown groups that tour the retro circuit but don’t include any original members? I remember reading an article years ago about how Motown or Berry Gordy owned the rights to the group names and would just assemble a group to perform under a famous name with none of the original members being included.
I came here to post this. I just watched this documentary about Fairport yesterday. Also, just saw Richard Thompson last Friday in Pittsburgh.
This is off-topic, but something very similar happened with the comedy group The Three Stooges.
Stoogeophiles already know about the changes in lineup from Moe Howard-Shemp Howard-Larry Fine to Moe-Larry-Curly to Moe Larry Shemp again to Moe-Larry-Joe Besser- to More-Larry-“Curly Joe” de Rita (and almost to Moe-Emil Sitka- Curly Joe). After Larry’s stroke, Joe deRita formed “The New Three Stooges”, with Curly Joe-Mousie Garner-Frank Mitchell, but it didn’t last. That group had no Howards or Larry Fine, and thus fits this thread’s premise.
The “other” stooges listed above had all appeared with the Stooges in short subjects, and were “stooges” of Ted Healy. Emil Sitka was a frequent actor, famous for his “Hold Hands, you Lovebirds!” line in Brideless Groom. Frank Mitchell had actually replaced Shemp and arguably qualifies as a Stooge, but he only did so on stage (in 1929), not on film. Sitka only appeared as a Stooge in publicity photos, and AFAIK never performed on stage or film as a Stooge.
[QUOTE=buddha_david;18436598Yes is in a similar situation with Chris Squire stepping aside for cancer treatment, leaving no original members in the band (Steve Howe didn’t join until their 3rd album.)[/QUOTE]
Alas, Yes now has no original members left, due to the passing of Chris Squire.