diff --git a/Source/Modules/UIModules/PrefUI/VwrPrefPaneDictionary.swift b/Source/Modules/UIModules/PrefUI/VwrPrefPaneDictionary.swift
index a8300f0d..cc7ccb35 100644
--- a/Source/Modules/UIModules/PrefUI/VwrPrefPaneDictionary.swift
+++ b/Source/Modules/UIModules/PrefUI/VwrPrefPaneDictionary.swift
@@ -88,7 +88,7 @@ struct VwrPrefPaneDictionary: View {
                       PrefMgr.shared.userDataFolderSpecified = newPath
                       tbxUserDataPathSpecified = PrefMgr.shared.userDataFolderSpecified
                       BookmarkManager.shared.saveBookmark(for: url)
-                      (NSApp.delegate as! AppDelegate).updateDirectoryMonitorPath()
+                      (NSApp.delegate as? AppDelegate)?.updateDirectoryMonitorPath()
                     } else {
                       IMEApp.buzz()
                       if !bolPreviousFolderValidity {
diff --git a/Source/Modules/WindowControllers/CtlPrefWindow.swift b/Source/Modules/WindowControllers/CtlPrefWindow.swift
index 33d54bef..743eaf43 100644
--- a/Source/Modules/WindowControllers/CtlPrefWindow.swift
+++ b/Source/Modules/WindowControllers/CtlPrefWindow.swift
@@ -263,7 +263,7 @@ class CtlPrefWindow: NSWindowController {
         if LMMgr.checkIfSpecifiedUserDataFolderValid(newPath) {
           PrefMgr.shared.userDataFolderSpecified = newPath
           BookmarkManager.shared.saveBookmark(for: url)
-          (NSApp.delegate as! AppDelegate).updateDirectoryMonitorPath()
+          (NSApp.delegate as? AppDelegate)?.updateDirectoryMonitorPath()
         } else {
           IMEApp.buzz()
           if !bolPreviousFolderValidity {