diff --git a/native/Avalonia.Native/src/OSX/WindowBaseImpl.mm b/native/Avalonia.Native/src/OSX/WindowBaseImpl.mm
index 33ab1529fc1..205f1efbdf5 100644
--- a/native/Avalonia.Native/src/OSX/WindowBaseImpl.mm
+++ b/native/Avalonia.Native/src/OSX/WindowBaseImpl.mm
@@ -465,11 +465,21 @@ static void ActivateApplication() {
 }
 
 void WindowBaseImpl::CreateNSWindow(bool usePanel) {
+    // Anchor the content rect to the primary screen's origin. It's usually at (0,0), but can be offset while the
+    // display server is mid-reconfiguration. This ensures the window is always on a proper screen.
+    // See https://github.com/AvaloniaUI/Avalonia/issues/18895
+    NSPoint origin = NSZeroPoint;
+    NSArray<NSScreen*>* screens = [NSScreen screens];
+    if (screens.count > 0)
+        origin = screens.firstObject.frame.origin;
+
+    NSRect contentRect = NSRect { origin.x, origin.y, lastSize };
+
     if (usePanel) {
-        Window = [[AvnPanel alloc] initWithParent:this contentRect:NSRect{0, 0, lastSize} styleMask:NSWindowStyleMaskBorderless];
+        Window = [[AvnPanel alloc] initWithParent:this contentRect:contentRect styleMask:NSWindowStyleMaskBorderless];
         [Window setHidesOnDeactivate:false];
     } else {
-        Window = [[AvnWindow alloc] initWithParent:this contentRect:NSRect{0, 0, lastSize} styleMask:NSWindowStyleMaskBorderless];
+        Window = [[AvnWindow alloc] initWithParent:this contentRect:contentRect styleMask:NSWindowStyleMaskBorderless];
     }
 }
 
diff --git a/src/Avalonia.Native/WindowImplBase.cs b/src/Avalonia.Native/WindowImplBase.cs
index 8d7270dedea..1f7f4787880 100644
--- a/src/Avalonia.Native/WindowImplBase.cs
+++ b/src/Avalonia.Native/WindowImplBase.cs
@@ -51,11 +51,23 @@ internal override void Init(MacOSTopLevelHandle handle)
 
             base.Init(handle);
 
+            int defaultWidth = 0, defaultHeight = 0;
+
             var monitor = this.TryGetFeature<IScreenImpl>()!.AllScreens
                 .OrderBy(x => x.Scaling)
-                .First(m => m.Bounds.Contains(Position));
+                .FirstOrDefault(m => m.Bounds.Contains(Position));
+
+            if (monitor != null)
+            {
+                // Emulate Windows 7+ default window size behavior.
+                defaultWidth = (int)(monitor.WorkingArea.Width * 0.75d);
+                defaultHeight = (int)(monitor.WorkingArea.Height * 0.7d);
+            }
+
+            defaultWidth = Math.Max(defaultWidth, 300);
+            defaultHeight = Math.Max(defaultHeight, 200);
 
-            Resize(new Size(monitor.WorkingArea.Width * 0.75d, monitor.WorkingArea.Height * 0.7d), WindowResizeReason.Layout);
+            Resize(new Size(defaultWidth, defaultHeight), WindowResizeReason.Layout);
         }
 
         public void Activate()