Dying Light Message Board  

P.S : I never cheat online.

If you set the session settings to singleplayer VAC automatically disables, else you can set vac secure to off if you set the session to multiplayer/co-op

However i see some messages of lot of people who explain that they have been ban whereas they only play in single player (with mods i mean). I'm worried.

There's a new patch out (Hotfix 1.10.1) that disables VAC in co-op on LAN. No mention of offline aka single player campaigns or being super clear about using mods in this sneaky VAC ban hammer that we were informed of after the fact.

Patch (hotfix) 1.10.1 release notes:
* Disabled VAC when playing coop on LAN
* Fixed rare issue with infinite loading or crash when starting the game
steamcommunity.com/games/239140/announcements/detail/890954350960148626

In the menu, go to the Options>Online, and set VAC Secure Game to NO.

That will disable VAC for your game, that way you can cheat to you're heart's content and not worry about a ban.

Thanks you for your answers !

Can I get confirmation playing the game with the online setting as single player renders you safe to use the trainer?

The VAC setting needs to be turned off. So far I've used the trainer without issues and friends joined my game.
We should be safe if you keep vac off in your online settings.