Something in my steam_api64.dll is causing a particular game to not work properly. Need advice.

[Kartarius]

Good morning,

TL;DR: I think my steam_api64.dll file has become corrupted, defective, and/or has been altered in some way when it comes to a particular game (see the "Through some testing..." paragraph on how I arrived at this conclusion). After playing the game for 10 hours, buttons and keys stopped working. When I restarted the game, save files were gone. When I started a new game, I could get through the introduction, but as soon as I gained control of my character all buttons and keys stopped working (even though they worked before that point). I am not having this issue with any other game on Steam, not even from games by the same developer. I bought the game directly from the Steam store. I am not using mods, etc. Uninstalling and reinstalling doesn't work. Downloading the game onto a different computer doesn't work.


A more detailed explanation (see last big paragraph for my conclusion):

I've been having an issue with a game for almost a month now (the game in question is Final Fantasy III Pixel Remaster). It started when I entered a new floor of a dungeon. All buttons from my controller, as well as keyboard keys and mouse clicks, stopped working.

At first I thought I was having a weird crash. So I closed the game, and after some effort I got it running again. All of my save files were gone on top of data that the game collects (monsters encountered). I started a new game. I could name my characters, get through the introductory scene, scroll through dialogue, input commands for a battle, go through the Experience screen, and scroll through more dialogue. As soon as I got control of my character though, no buttons or keys or mouse clicks would work. Uninstalling and reinstalling the game was not resolving the issue.

I went back and forth with the video game company's customer support. I tried 18 different things to resolve the issue (most suggested by the customer support). Everything from updating drivers, to verifying the game on Steam, to disabling third party programs, to reinstalling Windows 10. However, they failed to address something I learned early on when trying to fix the issue: the game had the same issues if I downloaded it from my Steam Library onto a different computer. This was telling me that something may be wrong with my personal copy of the game in my Steam Library.

Through some testing, I found out the culprit was the steam_api64.dll file. If I replace the steam_api64.dll file in FFIII Pixel Remaster with the steam_api64.dll file of another game I own, the game doesn't work and Steam verification says the file is okay. If I use a steam_api64.dll file from somewhere else, the game works fine. I was able to get past the introduction, and get past the dungeon where the problem initially started. It remembers save files and all monsters encountered. The problem is I don't earn achievements--and if I verify the game files, the file will be replaced with the one in my library, causing all the issues to return.

Has anyone heard of this happening before? Does anyone have advice or can point me in the direction of someone who can help me out?

Have a good day.