I have a weird error I do not know how to fix relating to "IActiveBuildTargetChanged"

So, I went to a game programming/designing place for a week, and developed an adventure survival game. After transferring the files onto my computer I noticed two errors in the console that wouldn't let me run the game.

It says this:
Assets/Standard Assets/CrossPlatformInput/Scripts/MobileControlRig.cs(13,29): error CS0234: The type or namespace name `IActiveBuildTargetChanged' does not exist in the namespace `UnityEditor.Build'. Are you missing an assembly reference?

And another similar error:
Assets/Standard Assets/Utility/PlatformSpecificContent.cs(15,29): error CS0234: The type or namespace name `IActiveBuildTargetChanged' does not exist in the namespace `UnityEditor.Build'. Are you missing an assembly reference?

I clicked on the error, which opened up my MobileControlRig codes, and highlighted this statement in the coding:
, UnityEditor.Build.IActiveBuildTargetChanged

While developing the game my mentor helped me greatly with many of the issues I had (because he has experience of course) so I am not the most knowledgeable with coding and such. If anyone has a solution to this or more info/images on the subject, I'll be glad to help.

(I use VisualStudio to view my coding)

 

Same error here. Looking for solution as well.

 

I have the same error i need help