diff --git a/lib/private/Encryption/Keys/Storage.php b/lib/private/Encryption/Keys/Storage.php
index 3abdd745d034..19d947090b9c 100644
--- a/lib/private/Encryption/Keys/Storage.php
+++ b/lib/private/Encryption/Keys/Storage.php
@@ -345,6 +345,11 @@ protected function keySetPreparation($path) {
 	 * @param string $uid user id
 	 */
 	protected function setupUserMounts($uid) {
+		if ($this->root_dir !== '') {
+			// this means that the keys are stored outside of the user's homes,
+			// so we don't need to mount anything
+			return;
+		}
 		if (!is_null($uid) && $uid !== '' && $uid !== $this->currentUser) {
 			\OC\Files\Filesystem::initMountPoints($uid);
 		}
diff --git a/tests/lib/Encryption/Keys/StorageTest.php b/tests/lib/Encryption/Keys/StorageTest.php
index eeb3e6c2fb04..3943e4f98bd5 100644
--- a/tests/lib/Encryption/Keys/StorageTest.php
+++ b/tests/lib/Encryption/Keys/StorageTest.php
@@ -61,6 +61,8 @@ public function setUp() {
 			->disableOriginalConstructor()
 			->getMock();
 
+		$this->util->method('getKeyStorageRoot')->willReturn('');
+
 		$this->view = $this->getMockBuilder('OC\Files\View')
 			->disableOriginalConstructor()
 			->getMock();
@@ -79,6 +81,10 @@ public function setUp() {
 		$this->storage = new Storage($this->view, $this->util, $userSession);
 	}
 
+	public function tearDown() {
+		\OC\Files\Filesystem::tearDown();
+	}
+
 	public function testSetFileKey() {
 		$this->util->expects($this->any())
 			->method('getUidAndFilename')
@@ -277,6 +283,33 @@ public function testGetUserKeyShared() {
 		$this->assertTrue($this->isUserHomeMounted('user2'));
 	}
 
+	public function testGetUserKeyWhenKeyStorageIsOutsideHome() {
+		$this->view->expects($this->once())
+			->method('file_get_contents')
+			->with($this->equalTo('/enckeys/user2/files_encryption/encModule/user2.publicKey'))
+			->willReturn('key');
+		$this->view->expects($this->once())
+			->method('file_exists')
+			->with($this->equalTo('/enckeys/user2/files_encryption/encModule/user2.publicKey'))
+			->willReturn(true);
+
+		$user = $this->createMock(IUser::class);
+		$user->method('getUID')->willReturn('user1');
+		$userSession = $this->createMock(IUserSession::class);
+		$userSession->method('getUser')->willReturn($user);
+		$util = $this->createMock(\OC\Encryption\Util::class);
+		$util->method('getKeyStorageRoot')->willReturn('enckeys');
+		$storage = new Storage($this->view, $util, $userSession);
+
+		$this->assertFalse($this->isUserHomeMounted('user2'));
+
+		$this->assertSame('key',
+			$storage->getUserKey('user2', 'publicKey', 'encModule')
+		);
+
+		$this->assertFalse($this->isUserHomeMounted('user2'), 'mounting was not necessary');
+	}
+
 	/**
 	 * Returns whether the home of the given user was mounted
 	 *