diff --git a/src/Tracy/Debugger.php b/src/Tracy/Debugger.php
index b3b079757..716c319d2 100644
--- a/src/Tracy/Debugger.php
+++ b/src/Tracy/Debugger.php
@@ -146,7 +146,7 @@ public static function enable($mode = NULL, $logDirectory = NULL, $email = NULL)
 			self::$logDirectory = $logDirectory;
 		}
 		if (self::$logDirectory) {
-			if (!is_dir(self::$logDirectory) || !preg_match('#([a-z]:)?[/\\\\]#Ai', self::$logDirectory)) {
+			if (!is_dir(self::$logDirectory) || !preg_match('#([a-z]+:)?[/\\\\]#Ai', self::$logDirectory)) {
 				self::$logDirectory = NULL;
 				self::exceptionHandler(new \RuntimeException('Logging directory not found or is not absolute path.'));
 			}