Troubleshooting

Mods not loading in-game

For PAYDAY 3, the most common cause is a missing -fileopenlog launch argument.

Add -fileopenlog to Settings - Launch Options. Without it, Unreal Engine does not scan the ~mods/ directory and no PAYDAY 3 .pak mods will load regardless of what’s installed.

Other things to check:

• The mod’s toggle is on (not disabled).
• A higher-priority mod isn’t overriding it - try moving it lower in the list.
• The mod targets the active game and your installed game version.
• For PAYDAY 2 or PAYDAY: The Heist, the required loader is installed and working.

Game not detected on first launch

If Modrex can’t find the selected game automatically:

1. Go to Settings - Game Path and click Browse.
2. Navigate to the game’s installation root folder.
3. Click Select Folder - Modrex validates and saves the path.

On Xbox Game Pass, Modrex scans every fixed drive letter on your system for the Xbox install path. This can take a few seconds on the first PAYDAY 3 detection pass.

”Missing file” badge on a mod

This appears when Modrex’s state file references a file or folder that no longer exists on disk. This happens after manually deleting files or moving your game folder.

Either Reinstall the mod to re-download it, or right-click and select Uninstall to remove the stale entry. See Priority and state for how Modrex tracks this state.

Archive cannot be installed

If Modrex says it cannot tell where an archive installs, the archive likely belongs inside another mod or has a layout that does not identify a supported target. Follow the author’s instructions shown in the dialog, then install the files manually if needed.

Modrex won’t launch after a Windows update

Xbox Game Pass installs can lose their file permissions after major Windows updates. Run Modrex as administrator once to restore access, then relaunch normally.

Log file location

When reporting a bug, always attach the Modrex log file:

Windows   %LOCALAPPDATA%\Modrex\logs\Modrex.log
Linux     ~/.local/share/modrex/logs/Modrex.log

Open it directly from Settings - Open log file.

Get help by filing a GitHub issue or posting in the 🛠️support forum on Discord. Either way, include your OS, launcher, and the log file - issues without logs are much harder to diagnose.