diff --git a/MinecraftClient/Program.cs b/MinecraftClient/Program.cs
index 10c471dd..4c8c280e 100644
--- a/MinecraftClient/Program.cs
+++ b/MinecraftClient/Program.cs
@@ -408,12 +408,12 @@ namespace MinecraftClient
                 }
             }
             InternalConfig.Username = InternalConfig.Login;
-            if (string.IsNullOrEmpty(Config.Main.General.Account.Password) && !useBrowser &&
+            if (string.IsNullOrEmpty(Config.Main.General.Account.Password) && string.IsNullOrEmpty(InternalConfig.Password) && !useBrowser &&
                 (Config.Main.Advanced.SessionCache == CacheType.none || !SessionCache.Contains(Settings.ToLowerIfNeed(InternalConfig.Login))))
             {
                 RequestPassword();
             }
-            else
+            else if (string.IsNullOrEmpty(InternalConfig.Password))
             {
                 InternalConfig.Password = Config.Main.General.Account.Password;
             }
diff --git a/MinecraftClient/Protocol/Handlers/Protocol18.cs b/MinecraftClient/Protocol/Handlers/Protocol18.cs
index f7ddda15..70670e4b 100644
--- a/MinecraftClient/Protocol/Handlers/Protocol18.cs
+++ b/MinecraftClient/Protocol/Handlers/Protocol18.cs
@@ -2236,7 +2236,7 @@ namespace MinecraftClient.Protocol.Handlers
         {
             try
             {
-                byte[] fields = dataTypes.GetAcknowledgment(acknowledgment, isOnlineMode);
+                byte[] fields = dataTypes.GetAcknowledgment(acknowledgment, isOnlineMode && Config.Signature.LoginWithSecureProfile);
 
                 SendPacket(PacketTypesOut.MessageAcknowledgment, fields);
 
@@ -2298,7 +2298,8 @@ namespace MinecraftClient.Protocol.Handlers
                 fields.AddRange(dataTypes.GetLong(timeNow.ToUnixTimeMilliseconds()));
 
                 List<Tuple<string, string>>? needSigned = null;               // List< Argument Name, Argument Value >
-                if (playerKeyPair != null && isOnlineMode && Config.Signature.SignMessageInCommand && protocolVersion >= MC_1_19_Version)
+                if (playerKeyPair != null && isOnlineMode && protocolVersion >= MC_1_19_Version
+                    && Config.Signature.LoginWithSecureProfile && Config.Signature.SignMessageInCommand)
                     needSigned = DeclareCommands.CollectSignArguments(command);
 
                 if (needSigned == null || needSigned!.Count == 0)
@@ -2329,7 +2330,7 @@ namespace MinecraftClient.Protocol.Handlers
                 if (protocolVersion >= MC_1_19_2_Version)
                 {
                     // Message Acknowledgment
-                    fields.AddRange(dataTypes.GetAcknowledgment(acknowledgment!, isOnlineMode));
+                    fields.AddRange(dataTypes.GetAcknowledgment(acknowledgment!, isOnlineMode && Config.Signature.LoginWithSecureProfile));
                 }
 
                 SendPacket(PacketTypesOut.ChatCommand, fields);
@@ -2371,7 +2372,7 @@ namespace MinecraftClient.Protocol.Handlers
                     DateTimeOffset timeNow = DateTimeOffset.UtcNow;
                     fields.AddRange(dataTypes.GetLong(timeNow.ToUnixTimeMilliseconds()));
 
-                    if (!isOnlineMode || playerKeyPair == null || !Config.Signature.SignChat)
+                    if (!isOnlineMode || playerKeyPair == null || !Config.Signature.LoginWithSecureProfile || !Config.Signature.SignChat)
                     {
                         fields.AddRange(dataTypes.GetLong(0));   // Salt: Long
                         fields.AddRange(dataTypes.GetVarInt(0)); // Signature Length: VarInt
@@ -2397,7 +2398,7 @@ namespace MinecraftClient.Protocol.Handlers
                     if (protocolVersion >= MC_1_19_2_Version)
                     {
                         // Message Acknowledgment
-                        fields.AddRange(dataTypes.GetAcknowledgment(acknowledgment!, isOnlineMode));
+                        fields.AddRange(dataTypes.GetAcknowledgment(acknowledgment!, isOnlineMode && Config.Signature.LoginWithSecureProfile));
                     }
                 }
                 SendPacket(PacketTypesOut.ChatMessage, fields);
diff --git a/MinecraftClient/Scripting/ChatBot.cs b/MinecraftClient/Scripting/ChatBot.cs
index 9570fe25..bd171234 100644
--- a/MinecraftClient/Scripting/ChatBot.cs
+++ b/MinecraftClient/Scripting/ChatBot.cs
@@ -568,7 +568,7 @@ namespace MinecraftClient
             //User-defined regex for private chat messages
             if (Config.ChatFormat.UserDefined && !string.IsNullOrWhiteSpace(Config.ChatFormat.Private))
             {
-                Match regexMatch = new Regex(Config.ChatFormat.Private).Match(text);
+                Match regexMatch = Regex.Match(text, Config.ChatFormat.Private);
                 if (regexMatch.Success && regexMatch.Groups.Count >= 3)
                 {
                     sender = regexMatch.Groups[1].Value;
@@ -679,7 +679,7 @@ namespace MinecraftClient
             //User-defined regex for public chat messages
             if (Config.ChatFormat.UserDefined && !string.IsNullOrWhiteSpace(Config.ChatFormat.Public))
             {
-                Match regexMatch = new Regex(Config.ChatFormat.Public).Match(text);
+                Match regexMatch = Regex.Match(text, Config.ChatFormat.Public);
                 if (regexMatch.Success && regexMatch.Groups.Count >= 3)
                 {
                     sender = regexMatch.Groups[1].Value;
@@ -782,7 +782,7 @@ namespace MinecraftClient
             //User-defined regex for teleport requests
             if (Config.ChatFormat.UserDefined && !string.IsNullOrWhiteSpace(Config.ChatFormat.TeleportRequest))
             {
-                Match regexMatch = new Regex(Config.ChatFormat.TeleportRequest).Match(text);
+                Match regexMatch = Regex.Match(text, Config.ChatFormat.TeleportRequest);
                 if (regexMatch.Success && regexMatch.Groups.Count >= 2)
                 {
                     sender = regexMatch.Groups[1].Value;
diff --git a/MinecraftClient/Settings.cs b/MinecraftClient/Settings.cs
index ee680ea2..7880ead0 100644
--- a/MinecraftClient/Settings.cs
+++ b/MinecraftClient/Settings.cs
@@ -969,7 +969,40 @@ namespace MinecraftClient
 
                 public string TeleportRequest = @"^([a-zA-Z0-9_]+) has requested (?:to|that you) teleport to (?:you|them)\.$";
 
-                public void OnSettingUpdate() { }
+                public void OnSettingUpdate()
+                {
+                    if (UserDefined)
+                    {
+                        bool checkResult = true;
+
+                        try { _ = new Regex(Public); }
+                        catch (ArgumentException)
+                        {
+                            checkResult = false;
+                            ConsoleIO.WriteLineFormatted("§cIllegal regular expression: ChatFormat.Public = " + Public);
+                        }
+
+                        try { _ = new Regex(Private); }
+                        catch (ArgumentException)
+                        {
+                            checkResult = false;
+                            ConsoleIO.WriteLineFormatted("§cIllegal regular expression: ChatFormat.Private = " + Private);
+                        }
+
+                        try { _ = new Regex(TeleportRequest); }
+                        catch (ArgumentException)
+                        {
+                            checkResult = false;
+                            ConsoleIO.WriteLineFormatted("§cIllegal regular expression: ChatFormat.TeleportRequest = " + TeleportRequest);
+                        }
+
+                        if (!checkResult)
+                        {
+                            UserDefined = false;
+                            ConsoleIO.WriteLineFormatted("§cChatFormat: User-defined regular expressions are disabled.");
+                        }
+                    }
+                }
             }
         }