diff --git a/src/main/java/moe/yushi/authlibinjector/transform/AuthlibLogInterceptor.java b/src/main/java/moe/yushi/authlibinjector/transform/AuthlibLogInterceptor.java
index d64dfcd..2c9e3c0 100644
--- a/src/main/java/moe/yushi/authlibinjector/transform/AuthlibLogInterceptor.java
+++ b/src/main/java/moe/yushi/authlibinjector/transform/AuthlibLogInterceptor.java
@@ -196,18 +196,23 @@ public class AuthlibLogInterceptor implements TransformUnit {
 	}
 
 	@Override
-	public Optional<ClassVisitor> transform(String className, ClassVisitor writer, Runnable modifiedCallback) {
+	public Optional<ClassVisitor> transform(ClassLoader classLoader, String className, ClassVisitor writer, Runnable modifiedCallback) {
 		if (className.startsWith("com.mojang.authlib.")) {
+			synchronized (interceptedClassloaders) {
+				if (interceptedClassloaders.contains(classLoader)) {
+					return Optional.empty();
+				}
+			}
 			return Optional.of(new ClassVisitor(ASM6, writer) {
 
 				@Override
 				public MethodVisitor visitMethod(int access, String name, String descriptor, String signature, String[] exceptions) {
 					MethodVisitor mv = super.visitMethod(access, name, descriptor, signature, exceptions);
 					if ("<clinit>".equals(name)) {
-						modifiedCallback.run();
 						mv.visitLdcInsn(Type.getType("L" + className.replace('.', '/') + ";"));
 						mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Class", "getClassLoader", "()Ljava/lang/ClassLoader;", false);
 						mv.visitMethodInsn(INVOKESTATIC, AuthlibLogInterceptor.class.getName().replace('.', '/'), "onClassLoading", "(Ljava/lang/ClassLoader;)V", false);
+						modifiedCallback.run();
 					}
 					return mv;
 				}
diff --git a/src/main/java/moe/yushi/authlibinjector/transform/ClassTransformer.java b/src/main/java/moe/yushi/authlibinjector/transform/ClassTransformer.java
index 42e4cb6..c1a8e6f 100644
--- a/src/main/java/moe/yushi/authlibinjector/transform/ClassTransformer.java
+++ b/src/main/java/moe/yushi/authlibinjector/transform/ClassTransformer.java
@@ -34,10 +34,12 @@ public class ClassTransformer implements ClassFileTransformer {
 		private String className;
 		private byte[] classBuffer;
 		private ClassWriter pooledClassWriter;
+		private ClassLoader classLoader;
 
-		public TransformHandle(String className, byte[] classBuffer) {
+		public TransformHandle(ClassLoader classLoader, String className, byte[] classBuffer) {
 			this.className = className;
 			this.classBuffer = classBuffer;
+			this.classLoader = classLoader;
 		}
 
 		public void accept(TransformUnit unit) {
@@ -49,7 +51,7 @@ public class ClassTransformer implements ClassFileTransformer {
 				pooledClassWriter = null;
 			}
 
-			Optional<ClassVisitor> optionalVisitor = unit.transform(className, writer, () -> currentModified = true);
+			Optional<ClassVisitor> optionalVisitor = unit.transform(classLoader, className, writer, () -> currentModified = true);
 			if (optionalVisitor.isPresent()) {
 				currentModified = false;
 				ClassReader reader = new ClassReader(classBuffer);
@@ -96,7 +98,7 @@ public class ClassTransformer implements ClassFileTransformer {
 					}
 				}
 
-				TransformHandle handle = new TransformHandle(className, classfileBuffer);
+				TransformHandle handle = new TransformHandle(loader, className, classfileBuffer);
 				units.forEach(handle::accept);
 				listeners.forEach(it -> it.onClassLoading(loader, className, handle.getFinalResult(), handle.getAppliedTransformers()));
 
diff --git a/src/main/java/moe/yushi/authlibinjector/transform/LdcTransformUnit.java b/src/main/java/moe/yushi/authlibinjector/transform/LdcTransformUnit.java
index f122366..3e6cf1f 100644
--- a/src/main/java/moe/yushi/authlibinjector/transform/LdcTransformUnit.java
+++ b/src/main/java/moe/yushi/authlibinjector/transform/LdcTransformUnit.java
@@ -9,7 +9,7 @@ import moe.yushi.authlibinjector.util.Logging;
 public abstract class LdcTransformUnit implements TransformUnit {
 
 	@Override
-	public Optional<ClassVisitor> transform(String className, ClassVisitor writer, Runnable modifiedCallback) {
+	public Optional<ClassVisitor> transform(ClassLoader classLoader, String className, ClassVisitor writer, Runnable modifiedCallback) {
 		return Optional.of(new ClassVisitor(ASM6, writer) {
 
 			@Override
diff --git a/src/main/java/moe/yushi/authlibinjector/transform/SkinWhitelistTransformUnit.java b/src/main/java/moe/yushi/authlibinjector/transform/SkinWhitelistTransformUnit.java
index 80822f6..54c610a 100644
--- a/src/main/java/moe/yushi/authlibinjector/transform/SkinWhitelistTransformUnit.java
+++ b/src/main/java/moe/yushi/authlibinjector/transform/SkinWhitelistTransformUnit.java
@@ -21,7 +21,7 @@ public class SkinWhitelistTransformUnit implements TransformUnit {
 	}
 
 	@Override
-	public Optional<ClassVisitor> transform(String className, ClassVisitor writer, Runnable modifiedCallback) {
+	public Optional<ClassVisitor> transform(ClassLoader classLoader, String className, ClassVisitor writer, Runnable modifiedCallback) {
 		if ("com.mojang.authlib.yggdrasil.YggdrasilMinecraftSessionService".equals(className)) {
 			return Optional.of(new ClassVisitor(ASM6, writer) {
 
diff --git a/src/main/java/moe/yushi/authlibinjector/transform/TransformUnit.java b/src/main/java/moe/yushi/authlibinjector/transform/TransformUnit.java
index f5b0231..c3de08a 100644
--- a/src/main/java/moe/yushi/authlibinjector/transform/TransformUnit.java
+++ b/src/main/java/moe/yushi/authlibinjector/transform/TransformUnit.java
@@ -5,6 +5,6 @@ import org.objectweb.asm.ClassVisitor;
 
 public interface TransformUnit {
 
-	Optional<ClassVisitor> transform(String className, ClassVisitor writer, Runnable modifiedCallback);
+	Optional<ClassVisitor> transform(ClassLoader classLoader, String className, ClassVisitor writer, Runnable modifiedCallback);
 
 }
diff --git a/src/main/java/moe/yushi/authlibinjector/transform/YggdrasilKeyTransformUnit.java b/src/main/java/moe/yushi/authlibinjector/transform/YggdrasilKeyTransformUnit.java
index e5fbe42..f8aebf8 100644
--- a/src/main/java/moe/yushi/authlibinjector/transform/YggdrasilKeyTransformUnit.java
+++ b/src/main/java/moe/yushi/authlibinjector/transform/YggdrasilKeyTransformUnit.java
@@ -23,7 +23,7 @@ public class YggdrasilKeyTransformUnit implements TransformUnit {
 	}
 
 	@Override
-	public Optional<ClassVisitor> transform(String className, ClassVisitor writer, Runnable modifiedCallback) {
+	public Optional<ClassVisitor> transform(ClassLoader classLoader, String className, ClassVisitor writer, Runnable modifiedCallback) {
 		if ("com.mojang.authlib.yggdrasil.YggdrasilMinecraftSessionService".equals(className)) {
 			return Optional.of(new ClassVisitor(ASM6, writer) {