A common frustration with Remote Desktop Connection (RDP) is that after switching from full screen to windowed mode, the session refuses to go back to full screen even when you click the maximize button. This issue is typically caused by a resolution mismatch between your local display and the RDP session. This guide covers the quick fix, the underlying causes, and multiple approaches to prevent the problem from recurring.

The Quick Fix: Ctrl+Alt+Break

The fastest solution is the keyboard shortcut:

Press Ctrl+Alt+Break to toggle the Remote Desktop window between full screen and windowed mode.

On keyboards that do not have a Break key (common on laptops), try these alternatives:

  • Ctrl+Alt+Pause (Pause and Break are often the same key)
  • Ctrl+Alt+Fn+B on some laptop keyboards
  • Use the on-screen keyboard: open osk.exe, then press Ctrl+Alt on your physical keyboard while clicking the Pause key on the on-screen keyboard

This shortcut works immediately regardless of resolution settings and is the go-to fix when you are stuck in windowed mode.

Why This Happens

Resolution Mismatch

When you start an RDP session, the connection is established at a specific resolution. If your local monitor resolution differs from the resolution the RDP session was configured with, the maximize button will only resize the window frame to fill your screen without entering true full screen mode.

Resolutions known to trigger this behavior include:

  • 1366 x 768 (common on older laptops)
  • Non-standard DPI scaling settings (125%, 150%)
  • Connecting from a higher-resolution display to a session started on a lower-resolution display

Multi-Monitor Configuration Changes

If you disconnect from an RDP session while using multiple monitors and then reconnect with a different monitor configuration (for example, undocking a laptop), the session may not return to full screen properly because the resolution context has changed.

Smart Sizing Interference

The Smart Sizing feature scales the remote desktop to fit the local window. While useful, it can interfere with full screen behavior if the session resolution does not match the display.

Configuring the RDP Connection for Full Screen

Using the Remote Desktop Connection GUI

  1. Open Remote Desktop Connection (mstsc.exe)
  2. Click Show Options to expand the settings
  3. Go to the Display tab
  4. Under Display configuration, drag the slider all the way to the right to Full Screen
  5. Ensure Use all my monitors for the remote session is checked if you want multi-monitor full screen
  6. Click Connect

Editing the .rdp File Directly

Every Remote Desktop connection can be saved as an .rdp file. You can edit this file with any text editor to control display behavior precisely.

Key display settings in the .rdp file:

# Force full screen mode
screen mode id:i:2

# Match the local desktop resolution (use 0 for full screen width/height)
desktopwidth:i:1920
desktopheight:i:1080

# Enable Smart Sizing (scales remote session to fit window)
smart sizing:i:1

# Use all monitors for the remote session
use multimon:i:1

# Span across monitors (older alternative to multimon)
span monitors:i:1

The screen mode id setting controls the display mode:

  • screen mode id:i:1 — Windowed mode
  • screen mode id:i:2 — Full screen mode

To resolve the full screen issue permanently for a specific connection, set screen mode id:i:2 and ensure the desktopwidth and desktopheight match your local display resolution.

Dynamic Resolution with Smart Sizing

Smart Sizing allows the remote desktop to scale within the window, which is useful when you frequently switch between full screen and windowed mode:

smart sizing:i:1

You can also enable this during a session:

  1. While connected in windowed mode, click the system menu icon in the title bar (or press Alt+Space)
  2. Select Smart Sizing

The remote desktop will now scale to fit whatever window size you choose, though text may appear blurry at non-native resolutions.

Registry Fixes

If the issue persists across all RDP connections, you can apply a registry fix on the local machine.

Fix Default RDP Display Settings

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client]
"DesktopWidth"=dword:00000780
"DesktopHeight"=dword:00000438

Adjust the hexadecimal values to match your display resolution. The values above correspond to 1920x1080.

Reset Remote Desktop Connection Cache

RDP caches connection settings in the registry and in .rdp files in your Documents folder. Clearing these can resolve persistent display issues:

  1. Delete the Default.rdp file from your Documents folder
  2. In the Registry Editor, navigate to: 
    HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client\Default
  3. Delete any stale entries that reference old monitor configurations

Multi-Monitor Considerations

Enabling Multi-Monitor Support

To use Remote Desktop across multiple monitors:

From the command line:

mstsc /multimon

In the .rdp file:

use multimon:i:1

In the GUI:

Go to the Display tab and check Use all my monitors for the remote session.

Span Mode vs. Multi-Monitor Mode

There are two approaches for using RDP with multiple monitors:

  • Span mode (/span) — Treats all monitors as a single large desktop. The remote session gets one virtual display that spans all monitors. The taskbar stretches across all screens.
  • Multi-monitor mode (/multimon) — The remote session recognizes each monitor independently. The taskbar appears on the primary monitor and windows can be maximized to individual monitors.

Multi-monitor mode is the preferred option and has been available since Windows 7 / Windows Server 2008 R2.

DPI Scaling Across Monitors

If your monitors have different DPI scaling settings, Remote Desktop may have trouble rendering at the correct size. In Windows 10 and later, you can enable per-monitor DPI support:

# Enable dynamic resolution updates on reconnect
dynamic resolution:i:1

This allows the RDP session to adjust its resolution when you move the window between monitors with different DPI settings.

Troubleshooting Steps

If the issue continues after trying the solutions above, work through these steps:

  1. Try Ctrl+Alt+Break first — This solves the immediate problem in almost all cases.
  2. Check your display scaling — Right-click the desktop, select Display settings, and verify the scale is set to 100% or a standard value.
  3. Update your RDP client — Ensure you are running the latest version of mstsc.exe or use the Microsoft Remote Desktop app from the Microsoft Store, which handles display scaling more gracefully.
  4. Update graphics drivers — Outdated GPU drivers can cause display rendering issues with RDP.
  5. Test with a new .rdp file — Create a fresh connection file rather than reusing one that may have cached incorrect display settings.
  6. Disable GPU acceleration in RDP — In the .rdp file, add: 
    redirectdirectx:i:0

Summary

The Remote Desktop full screen issue is almost always caused by a resolution mismatch between the RDP session and the local display. The keyboard shortcut Ctrl+Alt+Break is the fastest fix. For a permanent solution, configure your .rdp file with the correct resolution settings and screen mode id:i:2, or enable Smart Sizing to handle resolution differences gracefully. On multi-monitor setups, use the /multimon flag rather than span mode for the best experience.