As of 2021, Windows Defender (now called Microsoft Defender) is the #1 cause of this error. Here is exactly how to fix it:
The "missing" file rarely actually vanished. In 2021, many players found themselves in one of three scenarios: far cry 5 fcm64dll missing 2021
Locate (or newer versions like 2015-2019). Click Modify then Repair . As of 2021, Windows Defender (now called Microsoft
Title: Fix — Far Cry 5 “fcm64.dll missing” (2021) Body: If Far Cry 5 fails to launch with “fcm64.dll missing,” try these fixes in order: restart PC; run Ubisoft/Steam as admin; verify game files; install/repair Visual C++ redistributables (x64 & x86); update Windows and GPU drivers; check AV quarantine; run sfc /scannow; reinstall the game if needed. If nothing works, contact Ubisoft support with DxDiag and game logs. Click Modify then Repair
The most common reason for this error is a corrupted or deleted game file. Steam and Ubisoft Connect have built-in tools to scan your installation and replace missing files.