diff --git a/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift b/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
index 6ec989ab..98f9593a 100644
--- a/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
@@ -40,6 +40,7 @@ public protocol PrefMgrProtocol {
   var trimUnfinishedReadingsOnCommit: Bool { get set }
   var alwaysShowTooltipTextsHorizontally: Bool { get set }
   var clientsIMKTextInputIncapable: [String] { get set }
+  var onlyLoadFactoryLangModelsIfNeeded: Bool { get set }
   var useIMKCandidateWindow: Bool { get set }
   var handleDefaultCandidateFontsByLangIdentifier: Bool { get set }
   var shiftKeyAccommodationBehavior: Int { get set }
diff --git a/Packages/vChewing_Shared/Sources/Shared/Shared.swift b/Packages/vChewing_Shared/Sources/Shared/Shared.swift
index 74f494bb..f0c5da3c 100644
--- a/Packages/vChewing_Shared/Sources/Shared/Shared.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/Shared.swift
@@ -58,6 +58,7 @@ public enum UserDef: String, CaseIterable {
   case kTrimUnfinishedReadingsOnCommit = "TrimUnfinishedReadingsOnCommit"
   case kAlwaysShowTooltipTextsHorizontally = "AlwaysShowTooltipTextsHorizontally"
   case kClientsIMKTextInputIncapable = "ClientsIMKTextInputIncapable"
+  case kOnlyLoadFactoryLangModelsIfNeeded = "OnlyLoadFactoryLangModelsIfNeeded"
 
   case kUseIMKCandidateWindow = "UseIMKCandidateWindow"
   case kHandleDefaultCandidateFontsByLangIdentifier = "HandleDefaultCandidateFontsByLangIdentifier"
diff --git a/Source/Modules/AppDelegate.swift b/Source/Modules/AppDelegate.swift
index aac63946..e7f66e06 100644
--- a/Source/Modules/AppDelegate.swift
+++ b/Source/Modules/AppDelegate.swift
@@ -51,7 +51,7 @@ class AppDelegate: NSObject, NSApplicationDelegate, NSUserNotificationCenterDele
       NSUserNotificationCenter.default.deliver(userNotification)
     }
 
-    LMMgr.loadDataModelsOnAppDelegate()
+    if !PrefMgr.shared.onlyLoadFactoryLangModelsIfNeeded { LMMgr.loadDataModelsOnAppDelegate() }
     DispatchQueue.main.async {
       LMMgr.initUserLangModels()
       self.folderMonitor.folderDidChange = { [weak self] in
diff --git a/Source/Modules/PrefMgr.swift b/Source/Modules/PrefMgr.swift
index 1af72d7e..c1ad69dd 100644
--- a/Source/Modules/PrefMgr.swift
+++ b/Source/Modules/PrefMgr.swift
@@ -126,6 +126,13 @@ public class PrefMgr: PrefMgrProtocol {
   @AppProperty(key: UserDef.kClientsIMKTextInputIncapable.rawValue, defaultValue: ["com.valvesoftware.steam"])
   public var clientsIMKTextInputIncapable: [String]
 
+  @AppProperty(key: UserDef.kOnlyLoadFactoryLangModelsIfNeeded.rawValue, defaultValue: true)
+  public var onlyLoadFactoryLangModelsIfNeeded: Bool {
+    didSet {
+      if !onlyLoadFactoryLangModelsIfNeeded { LMMgr.loadDataModelsOnAppDelegate() }
+    }
+  }
+
   // MARK: - Settings (Tier 2)
 
   @AppProperty(key: UserDef.kUseIMKCandidateWindow.rawValue, defaultValue: false)
diff --git a/Source/Modules/ctlInputMethod_Core.swift b/Source/Modules/ctlInputMethod_Core.swift
index 43784396..478fb51e 100644
--- a/Source/Modules/ctlInputMethod_Core.swift
+++ b/Source/Modules/ctlInputMethod_Core.swift
@@ -177,7 +177,7 @@ class ctlInputMethod: IMKInputController {
       default:
         newInputMode = .imeModeNULL
     }
-    // LMMgr.loadDataModel(newInputMode)
+    if PrefMgr.shared.onlyLoadFactoryLangModelsIfNeeded { LMMgr.loadDataModel(newInputMode) }
 
     if inputMode != newInputMode {
       UserDefaults.standard.synchronize()