If you're on the Epic version, corrupt internal cache can cause the game to fail. You may need to manually clear the EGS cache folder to restore functionality.
Oddly, some high-end GPU users (like those with a 7900XT) found the game more stable when running on integrated graphics rather than their dedicated cards. Kingdom.Hearts.HD.1.5.and.2.5.ReMIX.Network.Fix...
For more detailed troubleshooting, you can check community discussions on the Kingdom Hearts Steam Forum or the PCGamingWiki page. If you're on the Epic version, corrupt internal
If you see a "Failed to create system data" error, it is often caused by Windows Security or Controlled Folder Access blocking the game from writing to your Documents folder. Whitelisting the game's executable in your antivirus settings can solve this. Essential Quality of Life Mods For more detailed troubleshooting, you can check community
For some versions, ensuring the offline=false setting is correctly toggled in configuration files (like epic_cemu for specific setups) allows the game to bypass certain online checks.