Game crash at launch

Checked integrity files leads to "all files successfully validated". Still, I cannot play.

EDIT: Ok so uninstalled ONI. Deleted ONI folder under Documents\Klei, deleted ONI folder under steam\steamapps ,etc....

Cleaned using CCleaner. And rebooted the laptop. Reinstalled everything from scratch. Now my game is starting. I'll re-enable mods and see.

I hope you'll be able to track down the issue anyway, to prevent further issues.

EDIT2: mods re-enabled, so far so good, no issue ^^

Edited December 31, 2020 by OxCD

I'm no expert, but the file referred to in the Assert "subworlds/barren/LargeChasmStart" seems to be part of the DLC and not vanilla. So it looks like something went wrong when your game got updated and some DLC stuff got mixed in. If you have cleared the whole ONI folder and it works now, I don't think you will ever see the issue again. There were many updates recently, both on vanilla and on DLC, so if you didn't play for a while your game may have updated the files in a mixed order.

Also, happy new year

I have the same problem with vanilla. But in the dlc, there is a radiation management tool in the sandbox. I tried it out a bit, that's all. next, I switch the mode to vanilla and can not not only download but also start a new game. the error is written 
Could not find Klei.AI.Disease: RadiationSickness

 at UnityEngine.Debug.LogError (System.Object message) [0x00000] in <b8388ffefd6046f8a7b4080349da72eb>:0 
 at Debug.LogError (System.Object obj) [0x00000] in <f30d3c85d1f64155aa0dc6c7adb0d1eb>:0 
 at ResourceSet`1[T].Get (System.String id) [0x00000] in <f30d3c85d1f64155aa0dc6c7adb0d1eb>:0 
 at SandboxToolParameterMenu.<ConfigureSettings>b__19_2 () [0x00000] in <1c58b1f98f5849baa9083bfd5185b144>:0 
 at SandboxSettings.<.ctor>b__41_2 (System.String data) [0x00000] in <1c58b1f98f5849baa9083bfd5185b144>:0 
 at SandboxSettings+Setting`1[T].set_Value (T value) [0x00000] in <1c58b1f98f5849baa9083bfd5185b144>:0 
 at SandboxSettings.SetStringSetting (System.String prefsKey, System.String value) [0x00000]

I reinstalled the game and all local files are fine

It seems that some old files from the DLC are getting stuck in the install folder. This should fix it:

1. Browse the Local Files (right-click ONI -> Properties -> Local Files -> Browse Local Files)
2. Go into the OxygenNotIncluded_Data folder and delete StreamingAssets
3. Verify Integrity of Game Files (right-click ONI -> Properties -> Local Files -> Verify Integrity of Game Files)

If you're having an issue with Sandbox, delete your kplayerprefs.yaml file found in Documents/Klei/OxygenNotIncluded. This file is auto-generated and mostly contains sandbox/debug settings.