If you are using a save file you didn't create, you must use a tool like Limebrella to input your AccountID (found in your Steam userdata folder) and "Resign" the file. Key Features You Can Edit
C:\Program Files (x86)\Steam\userdata\[Your ID]\2050650\remote\win64_save . re4 remake save editor verified
These GitHub-hosted tools are frequently used by the modding community to brute-force Steam IDs and convert save files between different versions of the game. How to Use an RE4 Remake Save Editor Safely If you are using a save file you
Because Capcom encodes saves with your unique Steam ID, simply downloading a "100% complete" file won't work without a tool to "resign" it to your account. How to Use an RE4 Remake Save Editor
Turn off Steam Cloud synchronization before editing. If the cloud detects a mismatch, it may overwrite your edited file with an old one.