This error means your Steam client or a game using Steam cannot find or access the required steamclient64.dll file.
Here’s how to fix it, from most likely to least likely.
Windows Key + I to open Settings.steamclient64.dll or Trojan:Win32/...This error essentially means the software is looking for a specific set of instructions (the DLL file) and either can't find it, or the file it found is "broken." Here is a straightforward guide to getting your library back up and running. 1. Restart Steam and Your PC unable to load library steamclient64.dll