All of the following criteria must be met

• All Requirements must be installed.
• Changed the title so that it doesn't just says "[Bug]: "
• I have searched the GitHub issues for my bug, even in the closed issues.

All of the following are optional to answer

• Tried reinstalling the Game.
• Tried reinstalling MelonLoader.
• Tried restarting PC.
• Was able to see the Start Screen.

Describe the issue.

its literally jsut stuck on the loading screen as soon as i press a save after i press start and it says "During invoking native->managed trampoline" and "[11:49:54.331] [BloonsTD6_Mod_Helper] Failed to save ShowRoundsetChanger for BloonsTD6 Mod Helper
[11:49:54.337] [BloonsTD6_Mod_Helper] System.IO.FileNotFoundException: Could not load file or assembly 'System.Security.Permissions, Version=0.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'. The system cannot find the file specified.
File name: 'System.Security.Permissions, Version=0.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'
at Newtonsoft.Json.Serialization.JsonTypeReflector.get_DynamicCodeGeneration()
at Newtonsoft.Json.Serialization.JsonTypeReflector.get_ReflectionDelegateFactory()
at Newtonsoft.Json.Serialization.DefaultContractResolver.GetDefaultCreator(Type createdType)
at Newtonsoft.Json.Serialization.DefaultContractResolver.InitializeContract(JsonContract contract)
at Newtonsoft.Json.Serialization.DefaultContractResolver.CreatePrimitiveContract(Type objectType)
at Newtonsoft.Json.Serialization.DefaultContractResolver.CreateContract(Type objectType)
at System.Collections.Concurrent.ConcurrentDictionary2.GetOrAdd(TKey key, Func2 valueFactory)
at Newtonsoft.Json.Utilities.ThreadSafeStore2.Get(TKey key) at Newtonsoft.Json.Serialization.DefaultContractResolver.ResolveContract(Type type) at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.GetContract(Object value) at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.GetContractSafe(Object value) at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value, Type objectType) at Newtonsoft.Json.JsonSerializer.SerializeInternal(JsonWriter jsonWriter, Object value, Type objectType) at Newtonsoft.Json.JsonSerializer.Serialize(JsonWriter jsonWriter, Object value) at Newtonsoft.Json.Linq.JToken.FromObjectInternal(Object o, JsonSerializer jsonSerializer) at Newtonsoft.Json.Linq.JToken.FromObject(Object o) at BTD_Mod_Helper.Api.ModOptions.ModSettingsHandler.SaveModSettings(BloonsMod mod, Boolean initialSave) [11:49:54.338] [BloonsTD6_Mod_Helper] Failed to save BypassSavingRestrictions for BloonsTD6 Mod Helper [11:49:54.338] [BloonsTD6_Mod_Helper] System.IO.FileNotFoundException: Could not load file or assembly 'System.Security.Permissions, Version=0.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'. The system cannot find the file specified. File name: 'System.Security.Permissions, Version=0.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' at Newtonsoft.Json.Serialization.JsonTypeReflector.get_DynamicCodeGeneration() at Newtonsoft.Json.Serialization.JsonTypeReflector.get_ReflectionDelegateFactory() at Newtonsoft.Json.Serialization.DefaultContractResolver.GetDefaultCreator(Type createdType) at Newtonsoft.Json.Serialization.DefaultContractResolver.InitializeContract(JsonContract contract) at Newtonsoft.Json.Serialization.DefaultContractResolver.CreatePrimitiveContract(Type objectType) at Newtonsoft.Json.Serialization.DefaultContractResolver.CreateContract(Type objectType) at System.Collections.Concurrent.ConcurrentDictionary2.GetOrAdd(TKey key, Func2 valueFactory) at Newtonsoft.Json.Utilities.ThreadSafeStore2.Get(TKey key)
at Newtonsoft.Json.Serialization.DefaultContractResolver.ResolveContract(Type type)
at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.GetContract(Object value)
at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.GetContractSafe(Object value)
at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value, Type objectType)
at Newtonsoft.Json.JsonSerializer.SerializeInternal(JsonWriter jsonWriter, Object value, Type objectType)
at Newtonsoft.Json.JsonSerializer.Serialize(JsonWriter jsonWriter, Object value)
at Newtonsoft.Json.Linq.JToken.FromObjectInternal(Object o, JsonSerializer jsonSerializer)
at Newtonsoft.Json.Linq.JToken.FromObject(Object o)
at BTD_Mod_Helper.Api.ModOptions.ModSettingsHandler.SaveModSettings(BloonsMod mod, Boolean initialSave)
[11:49:54.340] [BloonsTD6_Mod_Helper] Failed to save AutoHideModdedClientPopup for BloonsTD6 Mod Helper
[11:49:54.340] [BloonsTD6_Mod_Helper] System.IO.FileNotFoundException: Could not load file or assembly 'System.Security.Permissions, Version=0.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'. The system cannot find the file specified.
File name: 'System.Security.Permissions, Version=0.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'
at Newtonsoft.Json.Serialization.JsonTypeReflector.get_DynamicCodeGeneration()
at Newtonsoft.Json.Serialization.JsonTypeReflector.get_ReflectionDelegateFactory()
at Newtonsoft.Json.Serialization.DefaultContractResolver.GetDefaultCreator(Type createdType)
at Newtonsoft.Json.Serialization.DefaultContractResolver.InitializeContract(JsonContract contract)
at Newtonsoft.Json.Serialization.DefaultContractResolver.CreatePrimitiveContract(Type objectType)
at Newtonsoft.Json.Serialization.DefaultContractResolver.CreateContract(Type objectType)
at System.Collections.Concurrent.ConcurrentDictionary2.GetOrAdd(TKey key, Func2 valueFactory)
at Newtonsoft.Json.Utilities.ThreadSafeStore`2.Get(TKey key)
at Newtonsoft.Json.Serialization.DefaultContractResolver.ResolveContract(Type type)
at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.GetContract(Object value)
at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.GetContractSafe(Object value)
at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value, Type objectType)
at Newtonsoft.Json.JsonSerializer.SerializeInternal(JsonWriter jsonWriter, Object value, Type objectType)
at Newtonsoft.Json.JsonSerializer.Serialize(JsonWriter jsonWriter, Object value)
at Newtonsoft.Json.Linq.JToken.FromObjectInternal(Object o, JsonSerializer jsonSerializer)
at Newtonsoft.Json.Linq.JToken.FromObject(Object o)
at BTD_Mod_Helper.Api.ModOptions.ModSettingsHandler.SaveModSettings(BloonsMod mod, Boolean initialSave)
[11:49:54.341] [BloonsTD6_Mod_Helper] Failed to save CleanProfile for BloonsTD6 Mod Helper"

Did you attach your log file?

No, I could not find a log file at {Game_Directory}\MelonLoader\Latest.log

This has been resolved.
For the time being please downgrade to MelonLoader v0.6.1 on BTD6.