Terraria Community Forums

You need to install tmod from steam. The forums one isn’t supported anymore iirc.

but i need that to complete all my achievements because i need the ice scream achievement but i can only do it in december. if i did you the tmod from steam it would not count as an achievement

You don’t need to have it be in december. The frost moon has always been a year-round event (you can always craft the naughty present). It’s the frost LEGION that’s seasonal.

well, that's not the problem. the problem is that i can not use tmod.
i know that you can download from steam. i need to use tmod like i've been using for all these years and i need it for my achievements

The developers specifically said that because of some new sprites/redone mechanics, you cannot install it the old way. You will need to use the steam version.

Also, there’s a new method in 1.4 which allows you to get the halloween and christmas seasonal stuff year round, including the frost legion for that achievement.

An example of one of the reasons is that wavebanks were changed to support 88 songs, while tModloader can only support 41 in a wavebank and crashes it you try to load it with an 88 one. This is one of the minor reasons you can’t use the old method. The old method didn’t have take that into consideration because vanilla used a 41 song wavebank.