If your "portable" build is simply a standard installation folder that you copied to an external SSD, you can easily use an official launcher to scan and repair the missing file.
The three primary reasons why FC_m64.dll vanishes from a portable directory include:
The error in Far Cry 5 is a common roadblock, especially for players using portable versions or repacks. This file, often appearing as FC_m64.dll , is a critical Dynamic Link Library component of the Dunia Engine , which powers the game's physics and core systems. Why is FCM64.dll Missing?
If you want, I can:
A cautionary anecdote
Download and install the from the official Microsoft website.
The error regarding a missing (often referred to as FC_m64.dll
For a general guide on how to locate and replace missing DLL files for games: How to Fix EVERY missing DLL error in Windows 10/11 RGT Productions YouTube• Jun 3, 2025