diff --git a/AltStore/AppDelegate.swift b/AltStore/AppDelegate.swift
index ab55aaf3..49be4e2a 100644
--- a/AltStore/AppDelegate.swift
+++ b/AltStore/AppDelegate.swift
@@ -41,6 +41,9 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
 
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool
     {
+        // Register default settings before doing anything else.
+        UserDefaults.registerDefaults()
+        
         DatabaseManager.shared.start { (error) in
             if let error = error
             {
@@ -58,9 +61,7 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
         
         ServerManager.shared.startDiscovering()
         
-        SecureValueTransformer.register()
-        
-        UserDefaults.standard.registerDefaults()
+        SecureValueTransformer.register()        
         
         if UserDefaults.standard.firstLaunch == nil
         {
diff --git a/AltStoreCore/Extensions/UserDefaults+AltStore.swift b/AltStoreCore/Extensions/UserDefaults+AltStore.swift
index 041c62a0..4c0dfe3d 100644
--- a/AltStoreCore/Extensions/UserDefaults+AltStore.swift
+++ b/AltStoreCore/Extensions/UserDefaults+AltStore.swift
@@ -12,7 +12,15 @@ import Roxas
 
 public extension UserDefaults
 {
+    static let shared: UserDefaults = {
+        guard let appGroup = Bundle.main.appGroups.first else { return .standard }
+        
+        let sharedUserDefaults = UserDefaults(suiteName: appGroup)!
+        return sharedUserDefaults
+    }()
+    
     @NSManaged var firstLaunch: Date?
+    @NSManaged var requiresAppGroupMigration: Bool
     
     @NSManaged var preferredServerID: String?
     
@@ -42,16 +50,20 @@ public extension UserDefaults
     }
     @NSManaged @objc(activeAppsLimit) private var _activeAppsLimit: NSNumber?
     
-    func registerDefaults()
+    class func registerDefaults()
     {
         let ios13_5 = OperatingSystemVersion(majorVersion: 13, minorVersion: 5, patchVersion: 0)
         let isLegacyDeactivationSupported = !ProcessInfo.processInfo.isOperatingSystemAtLeast(ios13_5)
         let activeAppLimitIncludesExtensions = !ProcessInfo.processInfo.isOperatingSystemAtLeast(ios13_5)
         
-        self.register(defaults: [
+        let defaults = [
             #keyPath(UserDefaults.isBackgroundRefreshEnabled): true,
             #keyPath(UserDefaults.isLegacyDeactivationSupported): isLegacyDeactivationSupported,
-            #keyPath(UserDefaults.activeAppLimitIncludesExtensions): activeAppLimitIncludesExtensions
-        ])
+            #keyPath(UserDefaults.activeAppLimitIncludesExtensions): activeAppLimitIncludesExtensions,
+            #keyPath(UserDefaults.requiresAppGroupMigration): true
+        ]
+        
+        UserDefaults.standard.register(defaults: defaults)
+        UserDefaults.shared.register(defaults: defaults)
     }
 }
diff --git a/AltStoreCore/Model/DatabaseManager.swift b/AltStoreCore/Model/DatabaseManager.swift
index 26c44276..4a99ca0b 100644
--- a/AltStoreCore/Model/DatabaseManager.swift
+++ b/AltStoreCore/Model/DatabaseManager.swift
@@ -11,7 +11,7 @@ import CoreData
 import AltSign
 import Roxas
 
-private class PersistentContainer: RSTPersistentContainer
+fileprivate class PersistentContainer: RSTPersistentContainer
 {
     override class func defaultDirectoryURL() -> URL
     {
@@ -22,6 +22,11 @@ private class PersistentContainer: RSTPersistentContainer
 
         return databaseDirectoryURL
     }
+    
+    class func legacyDirectoryURL() -> URL
+    {
+        return super.defaultDirectoryURL()
+    }
 }
 
 public class DatabaseManager
@@ -35,6 +40,9 @@ public class DatabaseManager
     private var startCompletionHandlers = [(Error?) -> Void]()
     private let dispatchQueue = DispatchQueue(label: "io.altstore.DatabaseManager")
     
+    private let coordinator = NSFileCoordinator()
+    private let coordinatorQueue = OperationQueue()
+    
     private init()
     {
         self.persistentContainer = PersistentContainer(name: "AltStore", bundle: Bundle(for: DatabaseManager.self))
@@ -65,14 +73,21 @@ public extension DatabaseManager
             
             guard !self.isStarted else { return finish(nil) }
             
-            self.persistentContainer.loadPersistentStores { (description, error) in
-                guard error == nil else { return finish(error!) }
-                
-                self.prepareDatabase() { (result) in
-                    switch result
-                    {
-                    case .failure(let error): finish(error)
-                    case .success: finish(nil)
+            self.migrateDatabaseToAppGroupIfNeeded { (result) in
+                switch result
+                {
+                case .failure(let error): finish(error)
+                case .success:
+                    self.persistentContainer.loadPersistentStores { (description, error) in
+                        guard error == nil else { return finish(error!) }
+                        
+                        self.prepareDatabase() { (result) in
+                            switch result
+                            {
+                            case .failure(let error): finish(error)
+                            case .success: finish(nil)
+                            }
+                        }
                     }
                 }
             }
@@ -290,4 +305,75 @@ private extension DatabaseManager
             }
         }
     }
+    
+    func migrateDatabaseToAppGroupIfNeeded(completion: @escaping (Result<Void, Error>) -> Void)
+    {
+        guard UserDefaults.shared.requiresAppGroupMigration else { return completion(.success(())) }
+
+        func finish(_ result: Result<Void, Error>)
+        {
+            switch result
+            {
+            case .failure(let error): completion(.failure(error))
+            case .success:
+                UserDefaults.shared.requiresAppGroupMigration = false
+                completion(.success(()))
+            }
+        }
+        
+        let previousDatabaseURL = PersistentContainer.legacyDirectoryURL().appendingPathComponent("AltStore.sqlite")
+        let databaseURL = PersistentContainer.defaultDirectoryURL().appendingPathComponent("AltStore.sqlite")
+        
+        let previousAppsDirectoryURL = InstalledApp.legacyAppsDirectoryURL
+        let appsDirectoryURL = InstalledApp.appsDirectoryURL
+        
+        let databaseIntent = NSFileAccessIntent.writingIntent(with: databaseURL, options: [.forReplacing])
+        let appsIntent = NSFileAccessIntent.writingIntent(with: appsDirectoryURL, options: [.forReplacing])
+        
+        self.coordinator.coordinate(with: [databaseIntent, appsIntent], queue: self.coordinatorQueue) { (error) in
+            do
+            {
+                if let error = error
+                {
+                    throw error
+                }
+                
+                let description = NSPersistentStoreDescription(url: previousDatabaseURL)
+                
+                // Disable WAL to remove extra files automatically during migration.
+                description.setOption(["journal_mode": "DELETE"] as NSDictionary, forKey: NSSQLitePragmasOption)
+                
+                let persistentStoreCoordinator = NSPersistentStoreCoordinator(managedObjectModel: self.persistentContainer.managedObjectModel)
+                
+                // Migrate database
+                if FileManager.default.fileExists(atPath: previousDatabaseURL.path)
+                {
+                    if FileManager.default.fileExists(atPath: databaseURL.path, isDirectory: nil)
+                    {
+                        try FileManager.default.removeItem(at: databaseURL)
+                    }
+                    
+                    let previousDatabase = try persistentStoreCoordinator.addPersistentStore(ofType: description.type, configurationName: description.configuration, at: description.url, options: description.options)
+                    
+                    // Pass nil options to prevent later error due to self.persistentContainer using WAL.
+                    try persistentStoreCoordinator.migratePersistentStore(previousDatabase, to: databaseURL, options: nil, withType: NSSQLiteStoreType)
+                    
+                    try FileManager.default.removeItem(at: previousDatabaseURL)
+                }
+                
+                // Migrate apps
+                if FileManager.default.fileExists(atPath: previousAppsDirectoryURL.path, isDirectory: nil)
+                {
+                    _ = try FileManager.default.replaceItemAt(appsDirectoryURL, withItemAt: previousAppsDirectoryURL)
+                }
+                
+                finish(.success(()))
+            }
+            catch
+            {
+                print("Failed to migrate database to app group:", error)
+                finish(.failure(error))
+            }
+        }
+    }
 }
diff --git a/AltStoreCore/Model/InstalledApp.swift b/AltStoreCore/Model/InstalledApp.swift
index ca542ae9..2b521748 100644
--- a/AltStoreCore/Model/InstalledApp.swift
+++ b/AltStoreCore/Model/InstalledApp.swift
@@ -228,6 +228,12 @@ public extension InstalledApp
         return appsDirectoryURL
     }
     
+    class var legacyAppsDirectoryURL: URL {
+        let baseDirectory = FileManager.default.applicationSupportDirectory
+        let appsDirectoryURL = baseDirectory.appendingPathComponent("Apps")
+        return appsDirectoryURL
+    }
+    
     class func fileURL(for app: AppProtocol) -> URL
     {
         let appURL = self.directoryURL(for: app).appendingPathComponent("App.app")