Several factors could contribute to the Codex Save Game 100% issue:
Often includes a high Prestige level and maximum player rank. Typical Installation Path (CODEX) forza horizon 5 codex save game 100 fix
The default save location for the Forza Horizon 5 CODEX version is typically: C:\Users\Public\Documents\Steam\CODEX\1551360\remote Several factors could contribute to the Codex Save
If your save file isn't being created or is constantly corrupt: forza horizon 5 codex save game 100 fix