diff --git a/lib/private/legacy/util.php b/lib/private/legacy/util.php
index cef9f6e88a94..861b07b256d7 100644
--- a/lib/private/legacy/util.php
+++ b/lib/private/legacy/util.php
@@ -1439,8 +1439,8 @@ public static function isValidFileName($file) {
 			return false;
 		}
 
-		$path_parts = pathinfo($trimmed);
-		if ($path_parts['extension'] === 'part') {
+		// detect part files
+		if (preg_match('/' . \OCP\Files\FileInfo::BLACKLIST_FILES_REGEX . '/', $trimmed) !== 0) {
 			return false;
 		}
 
diff --git a/tests/lib/UtilTest.php b/tests/lib/UtilTest.php
index 241fd6d63297..442ece6dcce4 100644
--- a/tests/lib/UtilTest.php
+++ b/tests/lib/UtilTest.php
@@ -10,6 +10,9 @@
 
 use OC_Util;
 
+/**
+ * @group DB
+ */
 class UtilTest extends \Test\TestCase {
 	public function testGetVersion() {
 		$version = \OCP\Util::getVersion();
@@ -234,6 +237,13 @@ public function filenameValidationProvider() {
 			['.. ', false],
 			['. ', false],
 			[' .', false],
+			// part files not allowed
+			['.part', false],
+			['notallowed.part', false],
+			['neither.filepart', false],
+			// part in the middle is ok
+			['super movie part one.mkv', true],
+			['super.movie.part.mkv', true],
 		];
 	}