Errorcode -50 when removing trojan on a disk

We have no idea what you are referring to that you are trying to remove or where it is located. How is it that you identified this trojan? You can certainly provide screenshots as long as they do not include personal information.

How did you get the notification, that you might have malware on your Mac?

Did you already check this User Tip and follow the links mentioned?

What is malware? - Apple Community

Effective defenses against malware and ot… - Apple Community

Recognize and avoid social engineering schemes including phishing messages, phony support calls, and other scams - Apple Support