UE4 keeps crashing on startup

You’re trying to add a specific component that is already added. You should probably place a guard around that call to make sure you aren’t trying to add the component if it’s already setup.

if ( FindComponentByClass<UCameraComponent>() == nullptr )
{
    // Camera Component wasn't found, set it up.
}

Having error after I put this on MyPawn class: OurVisibleComponent->SetupAttachment(RootComponent);
Then my terminal error message:
[2017.03.16-14.32.54:661][ 0]LogLinux:Error: appError called: Assertion failed: Assertion failed: [File:/home/tiny/Documents/UnrealEngine-release/Engine/Source/Runtime/CoreUObject/Private/UObject/UObjectGlobals.cpp] [Line: 3714]
Default subobject CameraComponent RootComponent already exists for MyPawn /Script/Infiltrate1.Default__MyPawn.

Signal 11 caught.
Malloc Size=131076 LargeMemoryPoolOffset=131092

Hey ImDan-

Where in your code are you adding this line? If you comment out that line, are you able to open the project? If possible, please provide the full class where you’re adding this code.

Hey ImDan-

We have not heard back from you in a few days, so we are marking this post as Resolved for tracking purposes. If you are still experiencing the issue you reported, please respond to this message with additional information and we will follow up.

Cheers