Error copying System.Data.dll: File is missing. Although he is. How to fix?

Question

Windows

Error copying System.Data.dll: File is missing. What could it be? And the file is present! Literally about 8 minutes ago I made a build and everything was ok.

spoiler

I did not find answers on the Internet. Update: There is now a bug with missing System.Drawing.dll. What's a moron?!

Answer 1

If you are absolutely sure that the path is correct and the file was there, then maybe the antivirus nailed it?