diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/LaunchingUIDaemon.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/LaunchingUIDaemon.java
index ac9456cdc..d74ef360e 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/LaunchingUIDaemon.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/LaunchingUIDaemon.java
@@ -82,6 +82,7 @@ public class LaunchingUIDaemon {
         HMCLApi.EVENT_BUS.channel(JavaProcessStoppedEvent.class).register(event -> checkExit((LauncherVisibility) ((ProcessMonitor) event.getSource()).getTag()));
         HMCLApi.EVENT_BUS.channel(JavaProcessExitedAbnormallyEvent.class).register(event -> {
             int exitCode = event.getValue().getExitCode();
+            event.getValue().waitForCommandLineCompletion();
             HMCLog.err("The game exited abnormally, exit code: " + exitCode);
             String[] logs = event.getValue().getStdOutLines().toArray(new String[0]);
             String errorText = null;
diff --git a/HMCLAPI/src/main/java/org/jackhuang/hmcl/api/IProcess.java b/HMCLAPI/src/main/java/org/jackhuang/hmcl/api/IProcess.java
index ae173529b..a4dec1ca0 100644
--- a/HMCLAPI/src/main/java/org/jackhuang/hmcl/api/IProcess.java
+++ b/HMCLAPI/src/main/java/org/jackhuang/hmcl/api/IProcess.java
@@ -17,7 +17,6 @@
  */
 package org.jackhuang.hmcl.api;
 
-import java.util.ArrayList;
 import java.util.List;
 
 /**
@@ -34,10 +33,12 @@ public interface IProcess {
 
     List<String> getStartupCommands();
 
-    ArrayList<String> getStdOutLines();
+    List<String> getStdOutLines();
 
     boolean isRunning();
 
     void stop();
     
+    void waitForCommandLineCompletion();
+    
 }
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/util/sys/JavaProcess.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/util/sys/JavaProcess.java
index fa91a1f1d..2c6f25b37 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/util/sys/JavaProcess.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/util/sys/JavaProcess.java
@@ -18,9 +18,11 @@
 package org.jackhuang.hmcl.util.sys;
 
 import org.jackhuang.hmcl.api.IProcess;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Vector;
+import java.util.concurrent.CountDownLatch;
+import org.jackhuang.hmcl.api.HMCLog;
 
 /**
  *
@@ -28,9 +30,10 @@ import java.util.List;
  */
 public class JavaProcess implements IProcess {
 
+    private final CountDownLatch latch = new CountDownLatch(2);
     private final List<String> commands;
     private final Process process;
-    private final ArrayList<String> stdOutLines = new ArrayList<>();
+    private final Vector<String> stdOutLines = new Vector<>();
 
     public JavaProcess(List<String> commands, Process process) {
         this.commands = commands;
@@ -57,7 +60,7 @@ public class JavaProcess implements IProcess {
     }
 
     @Override
-    public ArrayList<String> getStdOutLines() {
+    public List<String> getStdOutLines() {
         return this.stdOutLines;
     }
 
@@ -72,6 +75,19 @@ public class JavaProcess implements IProcess {
         return false;
     }
 
+    CountDownLatch getLatch() {
+        return latch;
+    }
+
+    @Override
+    public void waitForCommandLineCompletion() {
+        try {
+            latch.await();
+        } catch (InterruptedException ignore) {
+            HMCLog.warn("Thread has been interrupted.", ignore);
+        }
+    }
+
     @Override
     public int getExitCode() {
         try {
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/util/sys/ProcessMonitor.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/util/sys/ProcessMonitor.java
index 06bc3245f..6bb61cbfc 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/util/sys/ProcessMonitor.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/util/sys/ProcessMonitor.java
@@ -77,13 +77,14 @@ public class ProcessMonitor {
         errorThread.start();
     }
 
-    private void threadStopped() {
+    private void threadStopped(SimpleEvent<IProcess> event) {
+        ProcessThread t = (ProcessThread) event.getSource();
         HMCLog.log("Process exit code: " + p.getExitCode());
-        if (p.getExitCode() != 0 || StrUtils.containsOne(p.getStdOutLines(),
+        if (p.getExitCode() != 0 || StrUtils.containsOne(t.getLines(),
                 Arrays.asList("Unable to launch"),
                 x -> Level.guessLevel(x, Level.INFO).lessOrEqual(Level.ERROR)))
             HMCLApi.EVENT_BUS.fireChannel(new JavaProcessExitedAbnormallyEvent(ProcessMonitor.this, p));
-        if (p.getExitCode() != 0 && StrUtils.containsOne(p.getStdOutLines(),
+        if (p.getExitCode() != 0 && StrUtils.containsOne(t.getLines(),
                 Arrays.asList("Could not create the Java Virtual Machine.",
                         "Error occurred during initialization of VM",
                         "A fatal exception has occurred. Program will exit.",
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/util/sys/ProcessThread.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/util/sys/ProcessThread.java
index 6595405c1..e25e492d7 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/util/sys/ProcessThread.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/util/sys/ProcessThread.java
@@ -21,6 +21,8 @@ import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.util.List;
+import java.util.Vector;
 import org.jackhuang.hmcl.api.HMCLog;
 import org.jackhuang.hmcl.api.event.EventHandler;
 import org.jackhuang.hmcl.api.event.SimpleEvent;
@@ -28,11 +30,13 @@ import org.jackhuang.hmcl.util.code.Charsets;
 import org.jackhuang.hmcl.api.IProcess;
 
 /**
+ * Watch the process command line output(stdout or stderr).
  *
  * @author huangyuhui
  */
 public class ProcessThread extends Thread {
 
+    Vector<String> lines = new Vector<>();
     ProcessMonitor monitor;
     boolean readError;
     public final EventHandler<SimpleEvent<String>> printlnEvent = new EventHandler<>();
@@ -48,6 +52,13 @@ public class ProcessThread extends Thread {
         return monitor.getProcess();
     }
 
+    /**
+     * Only get stdout or stderr output according to readError().
+     */
+    public List<String> getLines() {
+        return lines;
+    }
+
     @Override
     public void run() {
         setName("ProcessMonitor");
@@ -62,18 +73,22 @@ public class ProcessThread extends Thread {
                 while ((line = br.readLine()) != null) {
                     printlnEvent.fire(new SimpleEvent<>(monitor, line));
                     System.out.println("MC: " + line);
+                    lines.add(line);
                     p.getStdOutLines().add(line);
                 }
             while ((line = br.readLine()) != null) {
                 printlnEvent.fire(new SimpleEvent<>(monitor, line));
                 System.out.println("MC: " + line);
+                lines.add(line);
                 p.getStdOutLines().add(line);
             }
-            stopEvent.fire(new SimpleEvent<>(this, p));
         } catch (IOException e) {
             HMCLog.err("An error occured when reading process stdout/stderr.", e);
         } finally {
             IOUtils.closeQuietly(br);
         }
+        if (p instanceof JavaProcess)
+            ((JavaProcess) p).getLatch().countDown();
+        stopEvent.fire(new SimpleEvent<>(this, p));
     }
 }