diff --git a/HMCL/build.gradle b/HMCL/build.gradle
index d97a727a2..eba69212e 100644
--- a/HMCL/build.gradle
+++ b/HMCL/build.gradle
@@ -173,8 +173,13 @@ task proguard(type: proguard.gradle.ProGuardTask) {
 
     dontobfuscate
     dontoptimize
-    keep 'public class org.jackhuang.**'
-    keep 'public class org.slf4j.**'
+    dontpreverify
+    printusage
+
+    keep 'public class org.jackhuang.** { *; }'
+    keepclassmembers 'public class org.jackhuang.** { *; }'
+    keep 'public class com.jfoenix.** { *; }'
+    keepclassmembers 'public class com.jfoenix.** { *; }'
 
     dontwarn 'com.nqzero.**'
     dontwarn 'org.slf4j.**'
@@ -198,7 +203,6 @@ task proguard(type: proguard.gradle.ProGuardTask) {
         libraryjars "${javaHome}/lib/rt.jar"
         libraryjars "${javaHome}/lib/ext/jfxrt.jar"
     } else {
-        System.out.println(configurations.compileClasspath.collect())
         // As of Java 9, the runtime classes are packaged in modular jmod files.
         libraryjars "${javaHome}/jmods/java.base.jmod", jarfilter: '!**.jar', filter: '!module-info.class'
         libraryjars "${javaHome}/jmods/java.desktop.jmod", jarfilter: '!**.jar', filter: '!module-info.class'
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/setting/DownloadProviders.java b/HMCL/src/main/java/org/jackhuang/hmcl/setting/DownloadProviders.java
index 54cd170cb..80255da05 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/setting/DownloadProviders.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/setting/DownloadProviders.java
@@ -152,7 +152,7 @@ public final class DownloadProviders {
             } else if (exception.getCause() instanceof FileNotFoundException) {
                 return i18n("download.code.404", url);
             } else if (exception.getCause() instanceof AccessDeniedException) {
-                return i18n("install.failed.downloading.access_denied", url, ((AccessDeniedException) exception.getCause()).getFile());
+                return i18n("install.failed.downloading.detail", url) + "\n" + i18n("exception.access_denied", ((AccessDeniedException) exception.getCause()).getFile());
             } else {
                 return i18n("install.failed.downloading.detail", url) + "\n" + StringUtils.getStackTrace(exception.getCause());
             }
diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/setting/Theme.java b/HMCL/src/main/java/org/jackhuang/hmcl/setting/Theme.java
index db901e1bb..2e3d71ed3 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/setting/Theme.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/setting/Theme.java
@@ -31,6 +31,7 @@ import org.jackhuang.hmcl.util.javafx.BindingMapping;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.logging.Level;
 
@@ -55,7 +56,7 @@ public class Theme {
 
     Theme(String name, String color) {
         this.name = name;
-        this.color = color;
+        this.color = Objects.requireNonNull(color);
         this.paint = Color.web(color);
     }