diff --git a/apps/files_external/lib/Lib/Storage/SMB.php b/apps/files_external/lib/Lib/Storage/SMB.php
index f977bb1fe137f36a12d9b24d9f3b1ea04924cde8..a03324853ebecf7b5e2b19745227cf07b6a2ed9f 100644
--- a/apps/files_external/lib/Lib/Storage/SMB.php
+++ b/apps/files_external/lib/Lib/Storage/SMB.php
@@ -242,7 +242,7 @@ class SMB extends \OCP\Files\Storage\StorageAdapter {
 	}
 
 	/**
-	 * Rename the files
+	 * Rename the files. If the source or the target is the root, the rename won't happen.
 	 *
 	 * @param string $source the old name of the path
 	 * @param string $target the new name of the path
@@ -250,6 +250,12 @@ class SMB extends \OCP\Files\Storage\StorageAdapter {
 	 */
 	public function rename($source, $target) {
 		$this->log("enter: rename('$source', '$target')", Util::DEBUG);
+
+		if ($this->isRootDir($source) || $this->isRootDir($target)) {
+			$this->log("refusing to rename \"$source\" to \"$target\"");
+			return $this->leave(__FUNCTION__, false);
+		}
+
 		try {
 			$result = $this->share->rename($this->root . $source, $this->root . $target);
 			$this->removeFromCache($this->root . $source);
@@ -330,6 +336,12 @@ class SMB extends \OCP\Files\Storage\StorageAdapter {
 	 */
 	public function unlink($path) {
 		$this->log('enter: '.__FUNCTION__."($path)");
+
+		if ($this->isRootDir($path)) {
+			$this->log("refusing to unlink \"$path\"");
+			return $this->leave(__FUNCTION__, false);
+		}
+
 		$result = false;
 		try {
 			if ($this->is_dir($path)) {
@@ -442,6 +454,12 @@ class SMB extends \OCP\Files\Storage\StorageAdapter {
 
 	public function rmdir($path) {
 		$this->log('enter: '.__FUNCTION__."($path)");
+
+		if ($this->isRootDir($path)) {
+			$this->log("refusing to delete \"$path\"");
+			return $this->leave(__FUNCTION__, false);
+		}
+
 		$result = false;
 		try {
 			$this->removeFromCache($path);
diff --git a/apps/files_external/tests/Storage/SmbTest.php b/apps/files_external/tests/Storage/SmbTest.php
index 4cecb45d4163ed37931ff881ad208696e7238ec3..fdb7564a5e13c9bc76ed153ac5891b5b8fa6f6e1 100644
--- a/apps/files_external/tests/Storage/SmbTest.php
+++ b/apps/files_external/tests/Storage/SmbTest.php
@@ -87,4 +87,23 @@ class SmbTest extends \Test\Files\Storage\Storage {
 		$this->assertEquals('smb::testuser@testhost//someshare//someroot/', $this->instance->getId());
 		$this->instance = null;
 	}
+
+	public function testRenameRoot() {
+		// root can't be renamed
+		$this->assertFalse($this->instance->rename('', 'foo1'));
+
+		$this->instance->mkdir('foo2');
+		$this->assertFalse($this->instance->rename('foo2', ''));
+		$this->instance->rmdir('foo2');
+	}
+
+	public function testUnlinkRoot() {
+		// root can't be deleted
+		$this->assertFalse($this->instance->unlink(''));
+	}
+
+	public function testRmdirRoot() {
+		// root can't be deleted
+		$this->assertFalse($this->instance->rmdir(''));
+	}
 }