Try running GTAIV.exe as an administrator. If that fails, uninstall the Rockstar Games Launcher and re-install it through the game launcher, as it might be corrupted.

Open ProFixer.ini in Notepad. Here are the settings that matter:

To bridge this gap, community tools and manual optimization techniques—often collectively referred to as "GTA IV Pro Fixer" methods—have become essential. This comprehensive guide details how to permanently fix GTA IV's performance, graphics, and compatibility issues on modern Windows PCs. Why GTA IV Runs Poorly on Modern PCs

Which digital store version do you own? (e.g., , Rockstar Launcher , or Epic Games ?) What are your PC's graphics card and processor models?

Set to "Medium" or "High". "Very High" causes severe memory leaks.

Right-click an empty space, select , and click Text Document . Name this file exactly commandline.txt . Open the file and paste the following parameters:

This occurs when the game runs out of addressable system memory. Installing FusionFix or adding -nomemrestrict to your commandline.txt usually fixes this.

A comprehensive modification project that aims to fix map bugs, restore missing audio tracks removed due to expired music licenses, and clean up broken textures without altering the grim, cinematic atmosphere of Liberty City. Variety Graphic Shaders or ICEnhancer (Light Versions)

Corrects the infamous "broken menu scrolling" bug caused by high frame rates.

The Ultimate Guide to GTA IV Pro Fixer: How to Optimize Grand Theft Auto 4 for Modern PCs

This guide provides everything you need to know to fix GTA IV on modern Windows systems, optimize your performance, and achieve a flawless 60+ FPS experience. Why Grand Theft Auto IV Runs Poorly on PC

Because the "Pro Fixer" is an older utility, modern modding guides often recommend more comprehensive community fixes:

Download the latest version of from GitHub or trusted modding databases. Extract the contents of the zip file.

Download the latest DXVK release, copy the d3d9.dll from the x32 folder, and place it in the same directory as GTAIV.exe . 2. Fusion Fix Fusion Fix is an essential mod that fixes: Cutscenes running too fast/slow. Broken lighting on modern hardware. Adds ultrawide support and proper UI scaling. 3. ZolikaPatch

Because GTA IV's original DirectX 9 renderer struggles terribly on modern graphics cards, using DXVK to translate Direct3D calls into Vulkan will magically smooth out your frame times and remove the notorious choppiness. Download the latest DXVK binaries. Open the x32 folder inside the DXVK archive.

If you want a one-click automated solution, the community-created is the definitive "Pro Fixer" tool. It addresses structural bugs that cannot be fixed by command lines alone. Key Features of FusionFix:

These individuals act as unofficial developers. They reverse-engineer Rockstar’s code, strip out the broken DRM, inject modern DirectX support, and optimize the memory management. They do what the original developers often failed to do: future-proof the game.

If you want to fix the game manually without downloading a large mod pack, follow these steps:

-novblank : Disables vertical sync issues that cap frame rates arbitrarily.