diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/game/AccountHelper.java b/HMCL/src/main/java/org/jackhuang/hmcl/game/AccountHelper.java
index a3e50cc26..fdca46992 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/game/AccountHelper.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/game/AccountHelper.java
@@ -38,9 +38,10 @@ import java.util.Collection;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Optional;
+import java.util.UUID;
 
 public final class AccountHelper {
-    public static final AccountHelper INSTANCE = new AccountHelper();
+
     private AccountHelper() {}
 
     public static final File SKIN_DIR = new File(Launcher.HMCL_DIRECTORY, "skins");
@@ -73,8 +74,8 @@ public final class AccountHelper {
         return new SkinLoadTask(account, proxy, true);
     }
 
-    private static File getSkinFile(String name) {
-        return new File(SKIN_DIR, name + ".png");
+    private static File getSkinFile(UUID uuid) {
+        return new File(SKIN_DIR, uuid + ".png");
     }
 
     public static Image getSkin(YggdrasilAccount account) {
@@ -82,9 +83,11 @@ public final class AccountHelper {
     }
 
     public static Image getSkin(YggdrasilAccount account, double scaleRatio) {
-        if (account.getCharacter() == null)
-            return getDefaultSkin(account, scaleRatio);
-        File file = getSkinFile(account.getCharacter());
+        UUID uuid = account.getUUID();
+        if (uuid == null)
+            return getSteveSkin(scaleRatio);
+
+        File file = getSkinFile(uuid);
         if (file.exists()) {
             Image original = new Image("file:" + file.getAbsolutePath());
             return new Image("file:" + file.getAbsolutePath(),
@@ -92,15 +95,14 @@ public final class AccountHelper {
                     original.getHeight() * scaleRatio,
                     false, false);
         }
-        return getDefaultSkin(account, scaleRatio);
+        return getDefaultSkin(uuid, scaleRatio);
     }
 
     public static Image getSkinImmediately(YggdrasilAccount account, GameProfile profile, double scaleRatio, Proxy proxy) throws Exception {
-        String name = profile.getName();
-        File file = getSkinFile(name);
+        File file = getSkinFile(profile.getId());
         downloadSkin(account, profile, true, proxy);
         if (!file.exists())
-            return getDefaultSkin(account, scaleRatio);
+            return getDefaultSkin(profile.getId(), scaleRatio);
 
         String url = "file:" + file.getAbsolutePath();
         return scale(url, scaleRatio);
@@ -152,7 +154,7 @@ public final class AccountHelper {
         Optional<Texture> texture = account.getSkin(profile);
         if (!texture.isPresent()) return;
         String url = texture.get().getUrl();
-        File file = getSkinFile(profile.getName());
+        File file = getSkinFile(profile.getId());
         if (!refresh && file.exists())
             return;
         new FileDownloadTask(NetworkUtils.toURL(url), file, proxy).run();
@@ -165,7 +167,7 @@ public final class AccountHelper {
         Optional<Texture> texture = account.getSkin();
         if (!texture.isPresent()) return;
         String url = texture.get().getUrl();
-        File file = getSkinFile(account.getCharacter());
+        File file = getSkinFile(account.getUUID());
         if (!refresh && file.exists())
             return;
         new FileDownloadTask(NetworkUtils.toURL(url), file, proxy).run();
@@ -187,11 +189,8 @@ public final class AccountHelper {
         return scale("/assets/img/alex.png", 4);
     }
 
-    public static Image getDefaultSkin(Account account, double scaleRatio) {
-        if (account == null)
-            return getSteveSkin(scaleRatio);
-
-        int type = account.getUUID().hashCode() & 1;
+    public static Image getDefaultSkin(UUID uuid, double scaleRatio) {
+        int type = uuid.hashCode() & 1;
         if (type == 1)
             return getAlexSkin(scaleRatio);
         else
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/setting/Settings.java b/HMCL/src/main/java/org/jackhuang/hmcl/setting/Settings.java
index 679ec8f85..937ab255b 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/setting/Settings.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/setting/Settings.java
@@ -42,6 +42,7 @@ import java.net.InetSocketAddress;
 import java.net.PasswordAuthentication;
 import java.net.Proxy;
 import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.stream.Collectors;
 
@@ -62,13 +63,11 @@ public class Settings {
 
     public static final Settings INSTANCE = new Settings();
 
-    private Settings() {}
-
     private final Config SETTINGS = initSettings();
 
-    private final Map<String, Account> accounts = new HashMap<>();
+    private final Map<String, Account> accounts = new ConcurrentHashMap<>();
 
-    {
+    private Settings() {
         loadProxy();
 
         for (Iterator<Map<Object, Object>> iterator = SETTINGS.getAccounts().iterator(); iterator.hasNext(); ) {
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/AddAccountPane.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/AddAccountPane.java
index 782606e0f..d384855a1 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/AddAccountPane.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/AddAccountPane.java
@@ -64,8 +64,8 @@ public class AddAccountPane extends StackPane {
     @FXML private JFXComboBox<String> cboType;
     @FXML private JFXComboBox<TwoLineListItem> cboServers;
     @FXML private JFXProgressBar progressBar;
-    @FXML private Label lblAddInjectorServer;
-    @FXML private Hyperlink linkAddInjectorServer;
+    @FXML private Label lblInjectorServer;
+    @FXML private Hyperlink linkManageInjectorServers;
     @FXML private JFXDialogLayout layout;
     @FXML private JFXButton btnAccept;
     private final Consumer<Region> finalization;
@@ -82,8 +82,8 @@ public class AddAccountPane extends StackPane {
             txtPassword.setVisible(newValue.intValue() != 0);
             lblPassword.setVisible(newValue.intValue() != 0);
             cboServers.setVisible(newValue.intValue() == 2);
-            linkAddInjectorServer.setVisible(newValue.intValue() == 2);
-            lblAddInjectorServer.setVisible(newValue.intValue() == 2);
+            linkManageInjectorServers.setVisible(newValue.intValue() == 2);
+            lblInjectorServer.setVisible(newValue.intValue() == 2);
             validateAcceptButton();
         });
         cboType.getSelectionModel().select(0);
@@ -160,7 +160,7 @@ public class AddAccountPane extends StackPane {
     }
 
     @FXML
-    private void onAddInjecterServer() {
+    private void onManageInjecterServers() {
         finalization.accept(this);
         Controllers.navigate(Controllers.getServersPage());
     }
@@ -208,6 +208,7 @@ public class AddAccountPane extends StackPane {
                 try {
                     image = AccountHelper.getSkinImmediately(yggdrasilAccount, profile, 4, Settings.INSTANCE.getProxy());
                 } catch (Exception e) {
+                    Logging.LOG.log(Level.WARNING, "Failed to get skin for " + profile.getName(), e);
                     image = FXUtils.DEFAULT_ICON;
                 }
                 ImageView portraitView = new ImageView();
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/LeftPaneController.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/LeftPaneController.java
index 51f38a3b6..3fda2d12c 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/LeftPaneController.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/LeftPaneController.java
@@ -167,7 +167,7 @@ public final class LeftPaneController {
                 Image image = AccountHelper.getSkin((YggdrasilAccount) account, 4);
                 item.setImage(image, AccountHelper.getViewport(4));
             } else
-                item.setImage(AccountHelper.getDefaultSkin(account, 4), AccountHelper.getViewport(4));
+                item.setImage(AccountHelper.getDefaultSkin(account.getUUID(), 4), AccountHelper.getViewport(4));
 
             if (account instanceof AuthlibInjectorAccount)
                 Accounts.getAuthlibInjectorServerNameAsync((AuthlibInjectorAccount) account)
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/animation/TransitionHandler.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/animation/TransitionHandler.java
index 1dba20f34..81edd0a42 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/animation/TransitionHandler.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/animation/TransitionHandler.java
@@ -22,6 +22,7 @@ import javafx.animation.Timeline;
 import javafx.scene.Node;
 import javafx.scene.Parent;
 import javafx.scene.layout.StackPane;
+import javafx.scene.shape.Rectangle;
 import javafx.util.Duration;
 
 public final class TransitionHandler implements AnimationHandler {
@@ -36,6 +37,12 @@ public final class TransitionHandler implements AnimationHandler {
     public TransitionHandler(StackPane view) {
         this.view = view;
         currentNode = view.getChildren().stream().findFirst().orElse(null);
+
+        // prevent content overflow
+        Rectangle clip = new Rectangle();
+        clip.widthProperty().bind(view.widthProperty());
+        clip.heightProperty().bind(view.heightProperty());
+        view.setClip(clip);
     }
 
     @Override
diff --git a/HMCL/src/main/resources/assets/fxml/account-add.fxml b/HMCL/src/main/resources/assets/fxml/account-add.fxml
index 4361683f8..c08f1b2c8 100644
--- a/HMCL/src/main/resources/assets/fxml/account-add.fxml
+++ b/HMCL/src/main/resources/assets/fxml/account-add.fxml
@@ -25,13 +25,13 @@
 
                 <JFXComboBox fx:id="cboType" GridPane.columnIndex="1" GridPane.rowIndex="0" GridPane.columnSpan="2"/>
 
-                <Label fx:id="lblAddInjectorServer" text="%account.injector.server" GridPane.halignment="RIGHT"
+                <Label fx:id="lblInjectorServer" text="%account.injector.server" GridPane.halignment="RIGHT"
                        GridPane.columnIndex="0" GridPane.rowIndex="1"/>
 
                 <JFXComboBox fx:id="cboServers" maxHeight="25" GridPane.columnIndex="1" GridPane.rowIndex="1"/>
 
-                <Hyperlink fx:id="linkAddInjectorServer" text="%account.injector.add"
-                           onMouseClicked="#onAddInjecterServer" GridPane.columnIndex="2" GridPane.rowIndex="1"/>
+                <Hyperlink fx:id="linkManageInjectorServers" text="%account.injector.manage"
+                           onMouseClicked="#onManageInjecterServers" GridPane.columnIndex="2" GridPane.rowIndex="1"/>
 
                 <Label text="%account.username" GridPane.rowIndex="2" GridPane.columnIndex="0"/>
 
diff --git a/HMCL/src/main/resources/assets/lang/I18N.properties b/HMCL/src/main/resources/assets/lang/I18N.properties
index 2cbbff132..04c88fcf5 100644
--- a/HMCL/src/main/resources/assets/lang/I18N.properties
+++ b/HMCL/src/main/resources/assets/lang/I18N.properties
@@ -39,7 +39,8 @@ account.failed.invalid_credentials=Incorrect password. Or forbidden to log in te
 account.failed.invalid_password=Invalid password
 account.failed.invalid_token=Please log out and re-input your password to log in.
 account.failed.no_charactor=No character in this account.
-account.injector.add=Add new authentication server
+account.injector.add=Add authentication server
+account.injector.manage=Manage authentication servers
 account.injector.http=Warning: This server is using HTTP, which will cause your password be transmitted in clear text.
 account.injector.server=Auth Server
 account.injector.server_ip=Server URL
diff --git a/HMCL/src/main/resources/assets/lang/I18N_zh_CN.properties b/HMCL/src/main/resources/assets/lang/I18N_zh_CN.properties
index a92b97a13..a3d267d01 100644
--- a/HMCL/src/main/resources/assets/lang/I18N_zh_CN.properties
+++ b/HMCL/src/main/resources/assets/lang/I18N_zh_CN.properties
@@ -39,7 +39,8 @@ account.failed.invalid_credentials=您的用户名或密码错误，或者登录
 account.failed.invalid_password=无效的密码
 account.failed.invalid_token=请尝试登出并重新输入密码登录
 account.failed.no_charactor=该帐号没有角色
-account.injector.add=添加登录认证服务器
+account.injector.add=添加认证服务器
+account.injector.manage=管理认证服务器
 account.injector.http=警告：此服务器使用不安全的http协议，您的密码在登录时会被明文传输。
 account.injector.server=认证服务器
 account.injector.server_ip=服务器地址
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/yggdrasil/YggdrasilAccount.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/yggdrasil/YggdrasilAccount.java
index f6dcbb7ca..200449925 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/yggdrasil/YggdrasilAccount.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/auth/yggdrasil/YggdrasilAccount.java
@@ -145,7 +145,7 @@ public class YggdrasilAccount extends Account {
     }
 
     public UUID getUUID() {
-        if (session == null)
+        if (session == null || session.getSelectedProfile() == null)
             return null;
         else
             return session.getSelectedProfile().getId();