Terraria doesn't open through steam, and is laggy through the .exe file.

[TyTechnics]

I've read several forum pages about these problems, but I haven't found a solid answer yet.
So, my main problem is that when I open Terraria on Steam, it says that Terraria is preparing to launch, the preparing to launch tab disappears, then it says I am in Terraria. A few seconds later, I go back to being online, and Terraria doesn't open.

My second problem is that earlier in Terraria, (still in 1.3), I could launch Terraria through Steam, and (my real second problem) it wouldn't play in "Slow Motion". The problem is that when I open it through it's .exe file, the game feels like it's in slow motion.
By "slow motion", I mean that the game slightly lags to the point where it's unplayable, and it didn't do this when I played it last.

Please Help.

 

[SteveisNoob]

I've read several forum pages about these problems, but I haven't found a solid answer yet.
So, my main problem is that when I open Terraria on Steam, it says that Terraria is preparing to launch, the preparing to launch tab disappears, then it says I am in Terraria. A few seconds later, I go back to being online, and Terraria doesn't open.

When encountered, check the background processes on task manager. I had this issue several times and all of them was caused by terraria.exe stayed on background.(It works, but on background.)

My second problem is that earlier in Terraria, (still in 1.3), I could launch Terraria through Steam, and (my real second problem) it wouldn't play in "Slow Motion". The problem is that when I open it through it's .exe file, the game feels like it's in slow motion.
By "slow motion", I mean that the game slightly lags to the point where it's unplayable, and it didn't do this when I played it last.

It might caused by video settings, set the Frame Skip on if it set different. I had this issue a few times and all of it fixed when Frame Skip set to on.