diff --git a/virtualization.m b/virtualization.m
index 65ae862..874fa50 100644
--- a/virtualization.m
+++ b/virtualization.m
@@ -1207,13 +1207,16 @@ void sharedApplication()
 
 void startVirtualMachineWindow(void *machine, double width, double height)
 {
-    @autoreleasepool {
-        AppDelegate *appDelegate = [[[AppDelegate alloc]
-            initWithVirtualMachine:(VZVirtualMachine *)machine
-                       windowWidth:(CGFloat)width
-                      windowHeight:(CGFloat)height] autorelease];
+    if (@available(macOS 12, *)) {
+        @autoreleasepool {
+            AppDelegate *appDelegate = [[[AppDelegate alloc]
+                initWithVirtualMachine:(VZVirtualMachine *)machine
+                           windowWidth:(CGFloat)width
+                          windowHeight:(CGFloat)height] autorelease];
 
-        NSApp.delegate = appDelegate;
-        [NSApp run];
+            NSApp.delegate = appDelegate;
+            [NSApp run];
+        }
     }
+    RAISE_UNSUPPORTED_MACOS_EXCEPTION();
 }
diff --git a/virtualization_view.h b/virtualization_view.h
index e0935bc..ab00b92 100644
--- a/virtualization_view.h
+++ b/virtualization_view.h
@@ -6,6 +6,7 @@
 
 #pragma once
 
+#import <Availability.h>
 #import <Cocoa/Cocoa.h>
 #import <Virtualization/Virtualization.h>
 
@@ -22,6 +23,7 @@
 - (instancetype)init;
 @end
 
+API_AVAILABLE(macos(12.0))
 @interface AppDelegate : NSObject <NSApplicationDelegate, NSWindowDelegate, VZVirtualMachineDelegate>
 - (instancetype)initWithVirtualMachine:(VZVirtualMachine *)virtualMachine
                            windowWidth:(CGFloat)windowWidth