diff --git a/src/host/getset.cpp b/src/host/getset.cpp
index 7a088afb638..53a112d3fee 100644
--- a/src/host/getset.cpp
+++ b/src/host/getset.cpp
@@ -524,7 +524,24 @@ void ApiRoutines::GetLargestConsoleWindowSizeImpl(const SCREEN_INFORMATION& cont
         COORD const coordScreenBufferSize = screenInfo.GetBufferSize().Dimensions();
         if (size.X != coordScreenBufferSize.X || size.Y != coordScreenBufferSize.Y)
         {
-            RETURN_NTSTATUS(screenInfo.ResizeScreenBuffer(size, TRUE));
+            RETURN_IF_NTSTATUS_FAILED(screenInfo.ResizeScreenBuffer(size, TRUE));
+        }
+
+        // Make sure the viewport doesn't now overflow the buffer dimensions.
+        auto overflow = screenInfo.GetViewport().EndExclusive() - screenInfo.GetBufferSize().Dimensions();
+        if (overflow.X > 0 || overflow.Y > 0)
+        {
+            overflow = { std::max<SHORT>(overflow.X, 0), std::max<SHORT>(overflow.Y, 0) };
+            RETURN_IF_NTSTATUS_FAILED(screenInfo.SetViewportOrigin(false, -overflow, false));
+        }
+
+        // And also that the cursor position is clamped within the buffer boundaries.
+        auto& cursor = screenInfo.GetTextBuffer().GetCursor();
+        auto clampedCursorPosition = cursor.GetPosition();
+        screenInfo.GetBufferSize().Clamp(clampedCursorPosition);
+        if (clampedCursorPosition != cursor.GetPosition())
+        {
+            cursor.SetPosition(clampedCursorPosition);
         }
 
         return S_OK;
@@ -620,6 +637,23 @@ void ApiRoutines::GetLargestConsoleWindowSizeImpl(const SCREEN_INFORMATION& cont
         //  (see https://msdn.microsoft.com/en-us/library/windows/desktop/ms686125(v=vs.85).aspx and DoSrvSetConsoleWindowInfo)
         // Note that it also doesn't set cursor position.
 
+        // However, we do need to make sure the viewport doesn't now overflow the buffer dimensions.
+        auto overflow = context.GetViewport().EndExclusive() - context.GetBufferSize().Dimensions();
+        if (overflow.X > 0 || overflow.Y > 0)
+        {
+            overflow = { std::max<SHORT>(overflow.X, 0), std::max<SHORT>(overflow.Y, 0) };
+            RETURN_IF_NTSTATUS_FAILED(context.SetViewportOrigin(false, -overflow, false));
+        }
+
+        // And also that the cursor position is clamped within the buffer boundaries.
+        auto& cursor = context.GetTextBuffer().GetCursor();
+        auto clampedCursorPosition = cursor.GetPosition();
+        context.GetBufferSize().Clamp(clampedCursorPosition);
+        if (clampedCursorPosition != cursor.GetPosition())
+        {
+            cursor.SetPosition(clampedCursorPosition);
+        }
+
         return S_OK;
     }
     CATCH_RETURN();
diff --git a/src/host/renderData.cpp b/src/host/renderData.cpp
index 41d41d4d035..a84b95ac5e5 100644
--- a/src/host/renderData.cpp
+++ b/src/host/renderData.cpp
@@ -276,7 +276,7 @@ const std::vector<Microsoft::Console::Render::RenderOverlay> RenderData::GetOver
 // - <none>
 // Return Value:
 // - true if the cursor should be drawn twice as wide as usual
-bool RenderData::IsCursorDoubleWidth() const noexcept
+bool RenderData::IsCursorDoubleWidth() const
 {
     const CONSOLE_INFORMATION& gci = ServiceLocator::LocateGlobals().getConsoleInformation();
     return gci.GetActiveOutputBuffer().CursorIsDoubleWidth();
diff --git a/src/host/renderData.hpp b/src/host/renderData.hpp
index 26f291477d0..17172aba435 100644
--- a/src/host/renderData.hpp
+++ b/src/host/renderData.hpp
@@ -46,7 +46,7 @@ class RenderData final :
     CursorType GetCursorStyle() const noexcept override;
     ULONG GetCursorPixelWidth() const noexcept override;
     COLORREF GetCursorColor() const noexcept override;
-    bool IsCursorDoubleWidth() const noexcept override;
+    bool IsCursorDoubleWidth() const override;
 
     bool IsScreenReversed() const noexcept override;
 
diff --git a/src/host/screenInfo.cpp b/src/host/screenInfo.cpp
index 57edb1058e9..41b1a818c9a 100644
--- a/src/host/screenInfo.cpp
+++ b/src/host/screenInfo.cpp
@@ -2146,7 +2146,7 @@ void SCREEN_INFORMATION::SetViewport(const Viewport& newViewport,
     }
 
     // do adjustments on a copy that's easily manipulated.
-    SMALL_RECT srCorrected = newViewport.ToInclusive();
+    SMALL_RECT srCorrected = newViewport.ToExclusive();
 
     if (srCorrected.Left < 0)
     {
@@ -2160,16 +2160,16 @@ void SCREEN_INFORMATION::SetViewport(const Viewport& newViewport,
     }
 
     const COORD coordScreenBufferSize = GetBufferSize().Dimensions();
-    if (srCorrected.Right >= coordScreenBufferSize.X)
+    if (srCorrected.Right > coordScreenBufferSize.X)
     {
         srCorrected.Right = coordScreenBufferSize.X;
     }
-    if (srCorrected.Bottom >= coordScreenBufferSize.Y)
+    if (srCorrected.Bottom > coordScreenBufferSize.Y)
     {
         srCorrected.Bottom = coordScreenBufferSize.Y;
     }
 
-    _viewport = Viewport::FromInclusive(srCorrected);
+    _viewport = Viewport::FromExclusive(srCorrected);
     if (updateBottom)
     {
         UpdateBottom();