Why am I able to undo all my friend's spawns?

i am playing lan on mod and for some reason when i press undo i can delete my undo my friends stuff.

does anyone know how to fix this?

get a legal version of gmod/don’t use the same account for 2 people at once

I’m not sure whether this was fixed or not, but the theory behind it a few years ago was that all lan players used “STEAM_ID_LAN” as their SteamID.

Though I think the undo feature was changed to use a UniqueID rather than SteamID in the end.

Where did you get your version of Gmod?

Seeing as you already asked earlier how to LAN Gmod on the same account, I’d say, get another copy of the game.