diff --git a/src/main/scala/gitbucket/core/controller/AccountController.scala b/src/main/scala/gitbucket/core/controller/AccountController.scala
index c95f4fc..6e61b37 100644
--- a/src/main/scala/gitbucket/core/controller/AccountController.scala
+++ b/src/main/scala/gitbucket/core/controller/AccountController.scala
@@ -598,18 +598,19 @@
           // clone repository actually
           JGitUtil.cloneRepository(
             getRepositoryDir(repository.owner, repository.name),
-            getRepositoryDir(accountName, repository.name))
+            FileUtil.deleteIfExists(getRepositoryDir(accountName, repository.name)))
 
           // Create Wiki repository
-          JGitUtil.cloneRepository(
-            getWikiRepositoryDir(repository.owner, repository.name),
-            getWikiRepositoryDir(accountName, repository.name))
+          JGitUtil.cloneRepository(getWikiRepositoryDir(repository.owner, repository.name),
+            FileUtil.deleteIfExists(getWikiRepositoryDir(accountName, repository.name)))
 
           // Copy files
-          FileUtils.copyDirectory(
-            Directory.getRepositoryFilesDir(repository.owner, repository.name),
-            Directory.getRepositoryFilesDir(accountName, repository.name)
-          )
+          val repositoryFilesDir = getRepositoryFilesDir(repository.owner, repository.name)
+          if(repositoryFilesDir.exists){
+            FileUtils.copyDirectory(
+              repositoryFilesDir,
+              FileUtil.deleteIfExists(getRepositoryFilesDir(accountName, repository.name)))
+          }
 
           // Record activity
           recordForkActivity(repository.owner, repository.name, loginUserName, accountName)
diff --git a/src/main/scala/gitbucket/core/util/FileUtil.scala b/src/main/scala/gitbucket/core/util/FileUtil.scala
index 4f2a21d..e31dd6b 100644
--- a/src/main/scala/gitbucket/core/util/FileUtil.scala
+++ b/src/main/scala/gitbucket/core/util/FileUtil.scala
@@ -68,9 +68,24 @@
 
   def readableSize(size: Long): String = FileUtils.byteCountToDisplaySize(size)
 
+  /**
+   * Delete the given directory if it's empty.
+   * Do nothing if the given File is not a directory or not empty.
+   */
   def deleteDirectoryIfEmpty(dir: File): Unit = {
     if(dir.isDirectory() && dir.list().isEmpty) {
       FileUtils.deleteDirectory(dir)
     }
   }
+
+  /**
+   * Delete file or directory forcibly.
+   */
+  def deleteIfExists(file: java.io.File): java.io.File = {
+    if(file.exists){
+      FileUtils.forceDelete(file)
+    }
+    file
+  }
+
 }