Progress prevention

Progress prevention (also known as Unwinnable) are glitches that can prevent progress from being advanced further or objectives from being completed.

The Sims

 * Mimi Clean glitch: In The Sims Bustin' Out, there is an objective to clean Mimi's house. If objects were placed that prevented Sims from reaching that area, the trash would be in that space where the Sim cannot get to. This makes it impossible to complete the goal. The only workaround is to move objects around so that Sims can easily reach it.
 * Trash glitch: In The Urbz: Sims in the City for GBA and DS, if the trash was sold before the objective to recycle 100 piles of trash appears, it cannot be completed. The only way to fix this is to start a new game. It's possible to use a cheating device such as an Action Relay to give the player Trash.

The Sims 2

 * Meet an Alien glitch: This glitch affects the Meet an Alien want in The Sims 2 for Consoles.
 * Honest Jackson Secret glitch: If Ava arrives and the player doesn't socialize with Honest Jackson enough times to unlock his secret, the secret cannot be unlocked as Honest cannot be socialized. This only affects the DS version.

Windows and Mac OS X

 * Multi-Rabbit holes glitch: This glitch affects Opportunities that requires Rabbit holes. This glitch is only present in The Sims 3 Late Night. Later versions and The Sims 3 Pets for consoles fixed this glitch.

The Sims FreePlay

 * Check Mail glitch: On versions of FreePlay before 1.0.3, there was a progress prevention glitch that prevented the goal, Check your Mail, from being completed. As of 1.0.3, this glitch was fixed.
 * Add Sim to Town: In The Sims FreePlay version 1.x, If the player has 16 Sims when the player later gets the goal to Add a Sim to Town, a Sim can't be added and since Sims cannot be removed, there's no way to complete the goal. In version 2.0 this glitch was fixed since it is possible to remove a Sim and therefore another Sim can be added to complete the goal.