diff --git a/alt-tab-macos/logic/WindowManager.swift b/alt-tab-macos/logic/WindowManager.swift
index af8bed43..7b2a7a6c 100644
--- a/alt-tab-macos/logic/WindowManager.swift
+++ b/alt-tab-macos/logic/WindowManager.swift
@@ -9,7 +9,7 @@ class OpenWindow {
     var cgId: CGWindowID
     var cgTitle: String
     lazy var thumbnail: NSImage = computeThumbnail()
-    lazy var icon: NSImage = computeIcon()
+    lazy var icon: NSImage? = computeIcon()
 
     init(target: AXUIElement?, ownerPid: pid_t?, cgId: CGWindowID, cgTitle: String) {
         self.target = target
@@ -18,8 +18,8 @@ class OpenWindow {
         self.cgTitle = cgTitle
     }
 
-    func computeIcon() -> NSImage {
-        return NSRunningApplication(processIdentifier: ownerPid!)!.icon!
+    func computeIcon() -> NSImage? {
+        NSRunningApplication(processIdentifier: ownerPid!)?.icon
     }
 
     func computeThumbnail() -> NSImage {
diff --git a/alt-tab-macos/ui/Cell.swift b/alt-tab-macos/ui/Cell.swift
index 7779fe82..83fa9791 100644
--- a/alt-tab-macos/ui/Cell.swift
+++ b/alt-tab-macos/ui/Cell.swift
@@ -77,7 +77,7 @@ class Cell: NSCollectionViewItem {
         thumbnail.image!.size = NSSize(width: width, height: height)
         thumbnail.frame.size = NSSize(width: width, height: height)
         icon.image = element.icon
-        icon.image!.size = NSSize(width: Preferences.iconSize!, height: Preferences.iconSize!)
+        icon.image?.size = NSSize(width: Preferences.iconSize!, height: Preferences.iconSize!)
         icon.frame.size = NSSize(width: Preferences.iconSize!, height: Preferences.iconSize!)
         text.string = element.cgTitle
         // workaround: setting string on NSTextView change the font (most likely a Cocoa bug)