Dual Monitor Tools Not Working? Troubleshooting Guide
The fixes for the problems DMT users actually hit: dead hotkeys, cursor lock failing in games, monitors not detected, brightness controls greyed out.
Hotkeys not responding
- Run DMT as administrator: right-click DualMonitorTools.exe → Run as administrator. Windows blocks non-elevated apps from hooking elevated windows (Task Manager, many games and launchers).
- Check for conflicts: if another app (Discord, GeForce Experience, PowerToys) uses the same combo, DMT silently loses. Reassign to something obscure like Ctrl+Alt+Shift+L.
- Avoid reserved combos: Windows owns Win+L, Win+D, Win+Tab and friends — DMT can’t steal those.
Cursor lock fails in a game
- Use the hard “Lock cursor onto screen” hotkey, not sticky resistance — some engines bypass the hook sticky relies on.
- Run DMT as administrator if the game is elevated (most anti-cheat titles are).
- Press the lock hotkey after the game window has focus, not before.
Brightness / contrast controls do nothing
Enable DDC/CI in the monitor’s own menu
DMT talks to monitors over DDC/CI. If it’s disabled in your monitor’s OSD (it often is by default), the sliders do nothing. Enable it per-monitor, then restart DMT. Some monitors — especially over HDMI on laptops — simply don’t implement DDC/CI.
Settings lost after reinstall / update
Pro tips
- Back up
%appdata%\Dual Monitor Toolsbefore reinstalling: DmtSettings.xml, DmtMagicWords.xml, DmtWallpaperProviders.xml. - Portable (.zip) builds keep configs next to the exe; the MSI build uses AppData — migrating between them needs a manual copy.
Frequently Asked Questions
Why are my DMT hotkeys not working?
The two classic causes: another program already uses that key combination, or the target window runs as administrator while DMT doesn’t. Run DMT as administrator and pick combos Windows doesn’t reserve (avoid Win+Letter).
Why does DMT not detect my monitor?
DMT reads what Windows reports. Open Windows Display Settings first — if the monitor isn’t there, it’s a cable/driver issue, not DMT. Update your GPU driver, then restart DMT.
Where are DMT settings stored?
In %appdata%\Dual Monitor Tools (DmtSettings.xml, DmtMagicWords.xml, DmtWallpaperProviders.xml). Back these up before reinstalling — the MSI installer won’t migrate portable-edition configs automatically.
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