DnSpy ??

Supp bros? I'm C# Programmer and i do thinks, some times my thinks are shit, but trying to do it better.

Ok, so now my problem, some months ago i want to learn hacking c# code, cause is "easy" like Java (if not ofuscated) or that was i think.

So i hacked a POS software that i used some months, is to easy, hack the LicenseValidation Method and works like a charm (wow! what so hard!!) but now they do a new release, it looks exactly same in license validation, but now i do exactly the same thinks, just empty the method (not deleting it, or other code that calls this method will throw an exception) i compiled it and it sould works like my first hack, but there is a problem starting the program with my new file (Is a DLL the validation module, i not touch the .exe)

Ok, if you read that, im going to the problem, now when i execute that stupid program give me a critical Error "Could not load file or assembly 'System.Xml, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified."

if i google it, i found so many answer chaning the target in the config file, and many other thinks, but hey! im not have the project! Just the release, trying to change just a stupid method, without doing anything more. So its something with DnSpy? Or wrong .net framework version?

Hope you guys can iluminate my way.

Cheers.

EDIT: I dont know what i do with my DnSpy, but running it in another machine with Windows 7 (my PC have 10) it works like a charm. So, its windows? o im targeting wrong .net framework maybe?

the application probably detects changed files or dnspy gets detected just make sure it does not trigger or else the app won't start