Are Sims 3 mods safe

Answer 1

Mods, when they are programmed, installed and used correctly, can be safe to use without risking damage to game data or saved games. However, improperly installed mods or mods that do not work correctly can result in corrupt data, saved game losses, and severe glitches. That's why it is always good to take extra precautions and backup saved game data, like whole neighborhoods.

Some mods can corrupt objects or even cause malfunctions in the game code, resulting in one or more of the neighborhoods disappearing, which requires the game to be re-installed completely.

Modders are not generally malicious, and trouble with mods as often arises from errors on the players' behalf as on that of the modders'. For example, Awesome Mod's Configuration Tool is designed so that players who do not take the time to read instructions have the option to select a checkbox that will turn their installation of The Sims 3 into a "Big Fiery Ball Visible From Space", or "BFBVFS". Basically this is a trick for catching out irresponsible Simmers. Players should always read the instructions surrounding a mod, and never use options if they're not clear on what they do.

Many mods, when installed, conflict with other mods. This is especially true for core mods; only one core mod can be installed at a time. A mod designer may or may not be aware of these conflicts, so it is important to be careful when installing multiple mods. Additionally, some mods may corrupt saved games or game data if they are uninstalled incorrectly. If a mod must be uninstalled in a particular manner, the documentation that accompanied the mod should explain this. Mods that add additional skills in The Sims 3 are known to cause damage to sims who have earned a skill which was recently deleted. This will cause the player to have to delete their saved game.

Also, players are advised to check for updates every time they buy a new expansion or stuff pack. Out of date mods can cause save game files not to be loaded properly. Also, there is a chance that the game will be destroyed if it is ran with and out of date core mod. Patch 18 fixed the issue at some rate by not prompting the player if any out of date mods are installed.

Source: The sims wiki