Actor Existence Limbo

Acting and voice acting can be a fickle thing, but sometimes what can be simply corrected with The Other Darrin will not be possible; we call that the Actor Existence Limbo.

Actor Existence Limbo is when a Voice Actor worked on a series, but an incident caused the voice actor to be missing in action. Rather than replacing the VA, they make the character role unvoiced. So if the series requires voice acting, that person will go unvoiced or worse, an NPC if it was a game. Note that this does not extend to folks who are deceased or retired as they will simply find a replacement VA rather than kill them off, although not always.

In video games however, this can be simply dealt with by making a character unvoiced and an NPC.

One of the reasons why an Actor will be placed in limbo rather than replacing them is due to potential of bad publicity. Affairs can be called out by the press, possible grudges can happen between both sides. Simply put, an AEL can be harmful to those who enjoyed the actor.

When the character is plain killed off due the Actor Existence Limbo becoming too much, it becomes a case of McLeaned. When the network does this, it is a Role-Ending Misdemeanor. See also Demoted to Extra.

Examples of Actor Existence Limbo include:

Anime & Manga

In Crayon Shin-chan, Buriburizaemon was reduced to cameo appearances after his voice actor died in 2000.

Film

Wesley Snipes was serving a three-year prison sentence for tax evasion, which had officially delayed production on Blade 4 until at least fall 2013.

Video Games

Murphy Guyer didn't return for Neverwinter Nights 2: Mask of the Betrayer, and Ammon Jerro suddenly became an unvoiced NPC.
Bill gets this, and is later McLeaned, in Left 4 Dead 2 since they can't find his VA; Valve hinted that one survivor will die for real in the DLC chapter "The Passing".
Cagalli became unvoiced after Gundam Seed Destiny in Super Robot Wars since Naomi Shindo refused to reprise her role, so any games requiring her role will be a NPC only. The only moment she is playable so far is Super Robot Wars K (because K is on the DS and lacks voices). Dearka's voice actor also was missing in action since Destiny as well.
Averted with Guilty Gear: when Zato-1's voice actor passed away, the character remained in the series... technically. Zato-1 was losing control of his body to a sentient parasite named Eddie, who continued to use his body and appear under that name after Zato's death.
Star Trek Online having quests without voiced dialog isn't weird, being an MMO and all, but one arc of time travel quests had cameos of the The Original Series's cast over different missions. This means McCoy and Scotty (who were played by now dead actors) are placed in missions without voice acting, but Spock (Leonard Nemoy was alive at the time of production) is not.

Western Animation

Due to having numerous Celebrity Voice Actors, The Batman reduced many villains to cameo roles after their debut episodes. Poison Ivy, however, was featured prominently in a two-parter without any lines at all.
After already being replaced once, Valmont in Jackie Chan Adventures is reduced to a nonspeaking cameo in season five.
The Simpsons: After Phil Hartman's death, his characters (Lionel Hutz and Troy McClure) were reduced to cameos in group shots. Comic versions however continued to use the characters.
After Mako's death, Iroh from Avatar: The Last Airbender was relegated to only two silent appearances for the first half of season 3, before Greg Baldwin was introduced as his new voice.
- A bit of a subversion; those scripts were written before Mako's sad passing, and were always meant to have Iroh being silent. It was just very convenient. In fact, you can hear Baldwin step in for one scene in season 2 to get viewers used to his voice.